University of Wisconsin-Extension GEOLOGICAL AND NATURAL ...

University of Wisconsin-Extension
GEOLOGICAL AND NATURAL HISTORY SURVEY
3817 Mineral Point Road
Madison, Wisconsin 53705
M.E.. Ostrom, State Geologist and Director
A STRUCTURAL STUDY OF THE WAUSAU AREA
by
R..C.. Emmons and F..G.. Snyder
Open-File Report 45-3
16 p..
This report represents work performed by the Geological and
Natural History Survey, and is released to the open files in the
interest of making the information more readily available. This
report has not been edited or reviewed for conformity with
Geological and Natural History Survey standards and
nomenclature.

IIISCONSIN GEOLCGICAL SURVEY
A STRUCTURAL STUDY OF TIB VAUSAO AREA
B, C. Rmnona and F. G. Snyder
The area of this study includes twelve tmships, Tomships 28 to 30,
Range8 6 to BE. It is looated in Marathon County, Rimonsin, and includes the
City of Kausau in the east central part. It is orossed by U.S. Highmy No. 51
from north to south, by State Trzmk Highway No. 29 from east to west, end in pare
by State Tntnk Bighway No. 62 nhich leads from Rausau northeastward. Elsewhere
within the area are several county trunk highways end many secondary roads of good
quality. In general, roads are one-half mile to one mile epert.
There is considerable quarrying of granite, quartzite and argilllte with-
in the awe, which is devoted primarily to farming. Several attempts have been
made in tb past to exploit the occurrences of nepheline and zircon which have long
been kacrrm. Repheline, which is the chief objeotive of the present work, has not
been found in suitable iron free quality nor in sufficient quantity st the surface
for querrying operations.
The purpose of this study has been to learn the conditions under which
the nepheline deposits were formed with a viewr
(1) To delimiting the area of the nepheline occurrences.
(2) To determining something of the nature of the nepheline reserwa,
(3) To learning something about the faotors which determine the iron
content of ths nepheline.
For several years now it has eppeared that the nepheline owes its origin
and distribution locally to struotural factors within the area. Rth this in
mind tixis struotural study we8 underteken, and the results of the field '*.o?k are
offered here.
R@ ha- had the dietinot advantage of two separate pieoes 0.f work in the
erea to help us, tbt of Feidman, published as Bulletin 16 of the Geological Sur-
my of isc cons in 1907. and that of the Yiisconsin Geological Survey Meld pareies
of the early 19201s supplied to us as blue print township plats of the geclogy-
We have modified somewhat these interpretations but have drawn heavily on them,
as acknowledged in the accompanying map.
The rocks occurring here are volcanic flows and associated sediments over.-
lain by quartzite, later intruded by grsnite which diffemntisted into sever.61
types including the nepheline-bearing rocks, as a result largely of the str-dctural
control of the overlying roof rocks. I'ith this picture in mind the many rock
type8 found in the area are seen to be in considerable part modifications of the
few fundamental types, and the complex picture of the earlier mapping may be
simplifiet greatly by grouping the modi fications =der general heads. The fuds-
mental rock types and their mcdifications will therefore be discussed first.
Their mutual relationships will then be =ore easily described.
Rhyolite. The rhyolite is best exposed and occurs in larger bodiea in
the eastern portion of the area. The ma?ped rhyolite immediately east of lauss~
is well exposed and in considerable part is unsltered. Another excellent losaiitv

in which to study the rhyolite is Big Sandy Park where Big Sandy Creek cuts tb
rhyolite and proedes a continuous exposure for 100-200 yards and additional ex-
posures beyond.
In pnersl the rhyolite is a dark reddish or daik gray porphyritic rock,
massive in structuie and outcropping better than many other rooke of the district.
Tbe rhyolite matrix ie extremely fine-grained, much too fine-grained for field
study. The phenocrysts are feldspar and quar+z. The nature of the p3enocrysts
is not constant over the srea, being usually feldspar, sometimes quartz and commonly
feldspar with a little quartz. The feldspar is orthoclase at some localities, ia
usually plagioclase, aod locally includes both. The feldspar may be either vhite
or red, but is more commonly white in the darker rhyolite occurrences and is red
in the reddish rhyolite.
The Big Sandy Cmek exposure gave the best opportunity for study in the
area. The rocks appear on both sides of the stream as mll as in the bed. Ex-
posures sm good. Uost of the rock is rhyolite, mcst of the rhyolite is porphyritic,
the remainder (10-2%) is chlorite schist. Virtually all of the rhyolite is at
least somewhat sheamd. The matrix of the least sheared rhyolite is too fine-
grained for the Fmd lens butthe orthoclase phenocrysts are 1-2 nnn. long. They
shm up best on the weathered surface. The thickest beds are inclined to be
massive, are 20-25 feet thick; others are as thin as S feet. The original lithology
of tha thinner beds is a question since they have develcped schistcaity rather
consistently and am now chlorite schist. The attitude of the beds and rchistosity
$6 uniformly strike N75OEa dip BOOS, Original flow struoture in ths rhyolite is
quite commonly evident and in many beds is very marked.
fn ths aMa ncrthesst of l~ausau and southeast of Brckaw, the rhyolite was
cbserved mainly in surfaoe float rather than in outcrop. Eere much of the rhyolite
oarries only clear, glassy quartz phenocryste in eiihedral to scbtnedrrl form, and
having plentifbl inclusions of mapetite or chlorite. For the mcst part, hmver,
the rhyolite here carries plagioclase phenocrysts, re11 twinned, and nhite in
color. The matrix is very dark. Some of the rhyolite in this section is sheared
in which case it is quite light gray in oolor.
Directly east of Nausau, about one mlle from the city limits (NE~ HE;
Sac. 29, T 29 N, R 8 E), the rhyolite is agll exposed on ths crest of a southward
facing hill. The matrix is fine-grained. almost gleasy, medium gray in color and
carries phenocrysts of qusrez and plagioclase. The quartz is well rounded, and
is by no means abundant, possibly no more than one per cent of the rock. The
plagioclase phenocrysts constitute between five and ten per cent of the rock.
They am in subhsdral to euhedral crystals, 2-3 mm. in diameter, white in oolor
and well twinned on the albite-carlsbad complex law. The rook shms a very
massive character at this point. The outcrop does not pewit the detennination
of individusl flow thickness.
These descriptions apply to the rhyolite in its most nearly unaltered
form. The recognized modifioaticns of the rhyolite are of special interest since
the rhyolite is so closely associated with other rocks of critical interest in
the area, some of which bear a slight resembleme to modified rhyolite. A few
selected modified rhyolites may well be described. A common aspect of the rhyolite
where it is close to the intrusive splite or is out by aplitic apophyses is e
glassy medium gray lock, with or even without phenocrysts, in which the matrix
is distinctly spotted by chlorite in sm.11 grains or in aggregates. There the

aplite apophyses are large and numerous, such as imediately east of the city limits
of Pauseu on County Trunk Highway "N" and in the environs south of tho highway, the
rhyolite goes far to blend with the aplite through recrystallization. Apparently
this alteration does not extend far from the aplite-rbqolite contaot, possibly only
a few feet, though the epopy~es heve been observed to penetrate the rhyolite for
two or three hundred feet. m a
is illustrated on Higbiay "J" one mile north of
Highay "N" in SG SE*, Sac. 25, l' 29 IJ, R 8 E, and again on Highway "N" just east
of Vausau, though less olearly (South border Seo. 91. T 29 A, R 8 E).
Contiguous to the intntsim granite tb rhyolite is dark, even becoming
dioritio. This peculiarity is not easily explained since the contact selvage ia
higher in mafia constituents than is either the granite or the rhyolite. Bedrook
exposures are so meager in these places that only a suggestion can be offered in
explanstion. Fe have observed repeatedly thst the rhyolite darkens at intrusive
ooritaots with the granite and locally becomes highly mafic. This process of change
leads to a granite hybrid &ich ranges from granodiorite to mafic diorite. One
interpretation of these facts is thst the rhyolite passes doanward into more
vulnerable and mafio rock, such as greywacka or greenstone nbich yields the hybrid
mentioned. The rhyolite itself, being refractory, repels the intmsiw which Stops
progress after digesting the mfio material; hence the hybrid aaluage betaeen the
intrusive and the rhyolite.
The exposure of rhyolite on the north bank of the Eau Claire River just
east of the bridge near Kelly shows both the apophysal penetration of rhyolite by
apparent granite and the development of small plagi oclase laths thr ough recrystallieation,
in addition to the spotty ~ccmulation of msfic material already described.
Southesst of Schofield (in Sec, 20, T 28 E, R 8 8) the float indicates
the nearest approach to a gradation betmen aplite and rhyolite of any rook seen
in the area. Some of the rhyolite float here shows flow banding nhioh bears a
resemblance to the banded aplite seen elsewkere. Also shml here are various de-
grees of development of the mafic hybrid type from the rhyolite. Since, however,
none was found in plaoe, the oonclusions must be viithheld.
Another type of alteration of the rwolite is found in ST', SE~ of Sec. 26,
T SO H, R 6 E, Rhere the rhyolite has been sheared to prvduce a verynhite, very
fine-grained, apparently sericite schist. Them are quartz augen, apparently
phenocrysts, in the schist. The sohist cuts rhyolite which is here exposed in
the roadside.
It all1 be shown balm that muoh of the rhyolite of the map area and most
of the arriller rhyolitic bodies are shallow and yield downward to ap'ite or granite.
The reticulating dikes and veinlets which characterize much of the rhyolite are
to be interpreted as such contact effects and not as features of the rhyolite
itself.
Greenstone. Tee have chosen to include under this heading the following
rock types --- argillite, basalt. agglomerate, chloritic greenstone schist. and
hornblendite. V.e have done so with the thought thet all tkse rock types are
closely related, as will be shown. Although the dicritic and gsbbroic hybrids
could well be included here, we have chosen to classify them with the granite.
Actually they are contact phsses on a large scale.
The most abundant of the greenstone types is argillite which occur8 ex-
tensively wet the northern part of the map area. It is best expoaed for study
near the Fiscoasin River, where it outcrops in several places boldly and is also

* and quertzitio types.
revealed in road cuts. It includes both massive and banded typas, and both mafio
The beat exposure of tb argillite type la to be-fouml in the Bzukaw
quarry where the ergillits is being used for r~ofing granules. Outcrops to the
south of the quarry for a half mile are alsc good, especially in highway road cuts.
The surface six feet are badly jointed to produce the custcmry smsll, angular,
hand sire blocks so oonrmonly found as float where outcrops am lacking. Below
this the rook, though jointed is massive in large part. Some beds are badly
jointed as deeply as the cuts reveal them. The argillite may be divided into three
main types---banded ergillite, massive argillite, and qusr-ttitic argillite.
The banded argillite is perhaps the most common of the three. The band-
ing is not very evident on a freshly broken surface but ordinarily shows well on
a weathered surfaoe. In the quarry, hmever, the banding shows well on fresh sur-
faces in sum parts. The banding consists of color contrasts showing beds rang-
ing in thickness Dcm that of a sheet of paper to 1/4 inch. The bands are by no
means parallel but show marked lenticular form. Them is no evident contrnst in
grain size of oontiguous beds. Within beds there is furthsr banding, and overall
contrasts are evident in stratigraphic units six feet thick. But under the lens
all beds are cmposed of material beyond ~esolution. hn several of the exposums
south cf the quarry the bedding shows msrked folding, even cranulation, without
any appsrent increase in fracturing of the rock, this despite its hard siliceous
nature.
The massive argillite is a dark greenish gray rook for the most pert,
uniform in color and lacking evident structure. In places it carries wall one
millimeter spots of chloritic material but in most places is uniformly colorrd,
hard end massive. Specimens from different parts of an outcrop of massive
ergillite may show distinct color contrast but one is not conscious of the change
in the rock at any particular place.
One modification of the massive argillite shows strong development of
serpentine. This rock is strikingly massive and uniform and appears to be con-
fined to definite beds. It is not of infrequent occurrence but is much less
common than is the siliceous type.
Still anvther massive type of argillite, apparently of only occesional
occurrence, is one %ich has the appearance of being highly sericitized. It can
be scratched by a knife but alsc scratches the imife. It has an srgillaoecus
odor, its color is quite light gray, and its texture is beyond the reach of the
hand lens. It may be an alteration product near an intrusive contsct.
The most quartritic argillite seen is being quarrted in the Brokaw quarry.
This rock will undoubtedly prow uder the microscope to be novaculitic. It is
translucent, pale in color, in part rnsssive, in part bazded, extremely fine-
grajned, and breaks with a oonchoidel fracture. K'hen struck with e harrmer it has
a metallic ring.
Another excellent exposure cf argillite, most of which is finely banded,
is in a road cut on the east side of the V.isconsin River directly north of Yiausau
on Eighway "T." in Sec. 12, T 29 N, R 7 2. This rock is more chloritic than that
at the Brok8.w quarry but othemise is quite similar to it. Jt is well and finely

edded in the southern part of the exposure and quite massive in the northern part.
The exposure is sbout a quarbr mile long.
Elsewhere in the area greenatone occurs frequently but usually in small
autorops and mesksd by typically intense surface fraoturing. Also, it is commonly
modified by the closely underlying igneous intrusivsa, end is dissected by their
apophyses. This applies especially to the large areas of argillitio greenstone
in the north sad wet of the map area.
In two plases, agglomerate was found - one in the SE:, Seo. 12, T 29 R,
R 7 E. reached on Bighway "PIw north of Causau. It oocurs on a hillslde in a
pasture about 100 yards from the road. The other oocurs imediately south of the
Brdcaw quarry in a prominent rock out on the highway. In both occurrences tuff
end agglomerate are found together. Especially in the Brokaw occurrence the
larger fragments are rounded, giving the rock the aspect of a conglomerate. The
fragments are, hwwever, ell volcanic. The tuff and tuffaceous matrix of the
egglonerate is omposed of volcanic fragmants, highly angular in shape, variously
oolored and textured and dominantly uder 1/4 inch in size. This rock is compsra-
tively soft. espciallyrhen oompared to the argillite. It sppears to be keolinized
or aerioitized. Under the hand lens the entire rook appears too fine-grained for
resolution. Only by color contrast do the tuffaoeous and agglomsratic fragments
stand out. Varlous oolors are represented, mostly dark, the fine matrix is mostly
a mauve shade. The largest fragment seen in the agglomerate is one foot in diameter.
The majority of the fragments are one to four inches.
The hornblendite whioh is found only at two plaoes in the area (Sec. 33,
T 28 R, B 8 E, end Seo. IS. T 28 N, R 8 E) is a rook of unusual interest and sig-
nificance fn its connection with the structural history of the area. It is a
metsmorphio rock cauposed of large poikilitio hornblende crystals measuring ccmon-
ly over one inch across and in the extreua as large as three inches long in a
mstrix of dominant hornblende and a little feldspar. It is associated with green-
stone and granite.
Granite. It is probable that them are tvo granites in this area but no
field mexhod has been found to recognize the older of the two. It is possible
that tb granite of the rapids at Big Fiib Falls is the older granite but we are
unable to offer evidence. It is probable that the ovemhalming bulk of the granite
of the area is younger granite nhich is intrusive into all the rooks re resented
on the map. Included under the map designation "granite" are also the ybr.id rock
types, diorite and gabbro. Eost of the granite is red. T?hen contdnated by
greenstone, the granite becomes white or gray or even black and gabbroic.
The red granite, the common granite of the district, is by no meens uniform
even in those parts of the area which are presumably remote from foreign contmination.
From place to place there are differences in the or~hoclaseplagioclase ratio,
in the quartz content and even in the hornblende conterit. The presence of biotite
has been adopted es one indication of contamination by greenstone. Commonly. too,
the contaminated granite is gray rather th~n red, and is higl-er in mfio constituents
than is the common re6 granite. From place to place the red granite
texture shms differsnoes butthe most striking differences in texture are to be
found near locel contamination. A lite dikes seem to be a comon feature of the
granite, to be seen in almost my f arge exposure. Pepetite and lmpophyre dikes
are more limited to the vicinity of areas of foreign contect.
There an severe1 cjuar~iea in the red granite, in areas where the granite
is most "noml" and uniform. The granite at theae points is indeed rather. uni-
K

form. A typioal quarry granite of the PIausau area is feldspar 6%, including
both orthoclase and plagioolase, quarts S@, and usually a little chlorite. The
- texture is coarse granitic, about 6-6 mm. The rook is mssive and in the deeper
parts of the quarries is very widely jointed. Soms of the quarries show a
seriously large number of ohloritio paulopost v3inlets lrhich necessitate the dis-
carding of qusntities of othsmise marketable rook. Rarely ere inclusions a
problem in ths granite quarries of the husau area.
Areas of hybrid are quite numerous. A t;ipical example is that in the
northRrest corner of Sec. 54. T 29 El, R 6 E. Eere the rock is greenish gray, fine
granitic in texture (1-2 mu.) it is dominantly feldspr (a@), and carries about
15% of chlorite and hornblende. The quart8 content is about 6. As is charactsristio
of the granite hybrids in general, ths individual minerals appear to be
rnesked by an alter~tion such as sericltieationahich dep7ives them of the sharp
boundaries due to mlor contrast associated rith fresh granite.
Eybrids nay bti found in the area in all stages of reaction. Some such a8
that exposed at Big Rib Falls contain quantities of quite undigested greenstone.
Some, such as the exposure in the rock cut where County Trunk Highpiay "0" crosses
Steb Highway No. 29, show the greenstone vell recrystallized but by no means
granitic in texture except locally. Sme, such ss the exposurss in Sec. 25. T 29 R,
R 6 E, show tbs inclusions sa ghosts. This is also shown in a more edvansed stage
In Sec. 29. T SO N, R 8 8. A most extrame degree of reaction is illustrated by
the granite in ET& SE& Sac. 16. T 29 R, R 8 E. Here the rock is a biotite granite
carrylng about 1@ of biotite. Other illustrations could be given but ttese
illustrate adequately the principles involved. Usually the hybridisetlcn oan be
traced fran greenstone across the greenstone-granite contact almost anywhere with-
in the area, through the stages described out into biotite granite and finally into
that which we choose to recogzize as "normal" granite.
An attempt nas made to learn the depth to which the grsenstone influenoes
the granite. Tihere thia could best be ieamed, in the ncrthrestern prt, outcrops
are too soattered and we felt that mch critical information should nct depend on
float. Ia the northeast ocmer it can be said that one mila from the greenstone
the ganite shorn no recognicsble effect of the greenstone. This as6umes that tbe
contact is vertical since the measurement is mde on the present surfece. There
will be offered evidence that most of these oontacts have a wry lcm angle of dip
and doubtless therefore the stated mile can be reduced well below half th~t distance,
The mutual effect. of granite and greenstone may be of the type described
above, presumably thEI norm1 reaction men greonstone reacts with the main body
of the granite where diffusion is most free to operate. Another type cf hybrid-
ization and one less comonly seen is that which leads to the cornersion of green-
stone to dioritic and gabbrcic rook typs. There ere two localities within the
map area where such rocks have been fomd -- the ares around Callon and the area
sround XI: Rib Falls.
At Callon, the admixture of greenstons and gabbro in the reletionship of
en injected gneiss and the transition to homblendite at one point md to granite
to the north leaves little doubt about the origin of the gebbro. This rock is
about 5% fine-grained gabbro with occssional pegmatoid areas of amall size, the
remainder being banded ohloritic greenstone considerably recryatallixed to coarser
feldspr end sctinolite. It is composed of an estimated 65% of cslcic feldspar

and 35% sotlnolitio mphibole. The feldspar is medium grey in oolor and the
amphibole is green, not baaaltio. T b rock looks fresh. The texture is flne
granitio (2-5 m.) but pegmetoid phases aru coarser (about 6-8 nnrt.) and show up
espoially -11 on the weathered surfaoe. On the fresh break they are marked by
an especially strong developnt of mephibole. Throu&out the rook there is a
noiioeable tendency for the omon orientation of amphibole. This unphiibole is
darker in oolor than that of the run of the rock. It is the apparent beginning of
the formation of poikilitio hornblende porphyroblasts.
Tho greenstone inolusion phases am marked on a fresh break by mom chlorite
and by more ectinolltio tunphibole. The gabbroic phases shw a tendenc) for the
amphibole to become hornblendio. The greenstone phases am tharefors rery evident
on a weathered surfaoe, but by no mems evident on a fresh break.
The hornblendite in the gabbro area is oomposed of an estimated 7s hornblende.
and 2% oaloio feldspar. Muoh of the hornblende is porphyr~blaatic and
poikilitio. This rook appears to be malagous to the porpk~roblastic hornblendite
found in Seo. 35 ofthe same tomship, differing largely in the smaller size of
the hornblende orystals.
In the gabbroio area (mapped as granite) in the vicinity of Big Rib Falls
the took variations include many of the same type but also others. In S& SK:,
Se0.50, T29R. RGE, the rook is a sodio biotite diorite, a mafio hybrid-granite in
texture (1-4 mu.), and composed of about biotite and amphibole, BD+% oligoclaae
an? LC-+$ quarts. The rock is definitely patchy in its mineral distribution, 'even
to rlightly pegaatoid groupings. Assooiated with it is good granite aplits in
smell dikes. Nearby other rocks are oharaoterised by a diorltio appearwoe to
the naked eye but under the lens reveal a fine-grained matrix carrying lath-shaped
plagioclaae crystals (near sndesine) 2-3 m. long. The rook appears to be a reorystallized
argillite or even a basalt. And again elsewhere in the vicinity are
wtorops of granodiorItio rock. Good gabbro was found in this am@ as floe* but
not in outcrop. On the northeast side of Lclaer hTosinee Hill is sons g~bbio seen in
float only, ah&-ng a rermsrkebiy coarse, evan pegmetoid, texture, oarrying oalcic
plagioclsae. coarsely %nned, and actinolitio amphibole.
S--T
A lib. There cim thee areas of aplite umpped in this study, one in TZ9N.
RBE, one in T 8N, RBE, and the thira and largest in T29N, R6 end 7E. The rrecond
area mentioned is largely granite aplite, the first contains considerable good
sysnite aplits end the third is very largely syenite aplite. The third area is
very probably continuous under the alluvium kith the smeller areas of splits in
Little Rib Hi11 and in the hill to the met of Little Rib aoross the Little Rlb
River. Similar good quality syenite aplite is hom~ to us to occur errrund Rib
Mountain though this area has not been relnepped by us at this time. Tbe~e am
smaller syenite and granite aplite ooourrsnces but they are balieved to leek significance
in conneotioz with the present study.
In general the aplite is 1itholcgicaZly a true aplite charaoterised by the
customary fine, sugary texturn of crushed and recrystallized minerels. Tho rock
ia equigranular, except for a porphyritic variety in the T29N, RBE occurrence.
Under the microscope the component minerals cmonly show sutured boundaries. Much
of the aplite is apparently monomineralic, but most of it carries at least a little
amphibole or even biotite and as mentioned some of it carries quartz. The msfio
content is ebpecially vatiable and when high gives the splite a dark color. The
most normal color of the aplite is pink or some light shade of red. Variations

include white Mob is rather rare, brm vhich is more common, rich red which is
also oolmnon, and shades of green whioh become more rare in the darker shades.
An excellent exposure of the aplite where it carries quartz, is that just
north of Stata EigmPay 29 in and liEa of the NEi of Sec. 51, TZ913, R?E. Eere
the rock ehms soma range in tsxturs, stmoturs and in bornposition. It is rather
nsll banded, the bands being both fine (niicrosoopic) and cccsse (up to 3"). Some
of the beading is quite straight, some is wavy, none is orenulated, much is of
variable thiakneas. It is defined by differences in both texture and composition.
The campositional differences are the most evidept because of the greater mount
of biotite in some bands, giving thereby a color contrast. These differences are
tpical of the finer bands. The textural differwnoee are also somewhat oomposi-
tional. They characteri ze the coarser banding. These differences range from
coarse granitic (5 mm.) which is not oomon, through fine granitic (2-3 m.) whioh
is omon but only 5-1% of the rook, through aplitio (less than 1 mm.) which is
the bulk of the rook, to a tsxture which oan be desorlbed as truly rhyolitio.
Attontion is oalled to this last texture, which is in bands up to 1/2 inch end in
plaoss is more than 2% of the rook. Augen-like masses of rnafio mater5al f'rom a
small freotion of sn fnch up to S inches emphasize the general gneissio structure.
The ooaraer textural portions are also liberally arranged in this same augen-like
msnner. The attitude of the banding is fairly uniform.
Yineralogioally the rock is for the most part a granite aplite. Lesser
variations exbend to granite at one sxtrmm nnd to quartz syenite aplite at the
other O%tm?ne. None of the rock can properly be oalled a syenite or a syenite
aplite at this locality. It fa composed of dominantly orthoclase feldspar, with
prominent oarlabad tmins. Them is a little plagioclase feldspar, which is appar-
ently quite sodio. Quartz ranges from 10-#$ and averages 15-2056. The mafio
mineral is biotite in flakas and aggragstes, bth quite lineally distributed.
Another excellent exposum of aplltw my be fcund at the north end of the
shns quartzite-capped hill, in fi~4 ~ 2 Sec. , 29, T29N, R7E. This is perhaps one
of the best available exposures, in tbht a good section is offered for a depth of
at least 60 feet. The rock ahous many varieties of the aplite whloh occurs belm
the quartzite. The aplite is canposed of orthoclase feldspar, black amphibole and
in some perts quartz. Soma of the rook is composed cf pure feldspar. Most oontains
in rdditlon 15-1% of amphibole. A small part, of the rook contains a little quartz.
in plaoes reaching st most 2%. The feldspar is pmse.lt also as occasional phenocrysts
in size up to 2 om. Most of the feldspar is Carlsbad twinned. Grain size
of the matrix covers a range frm oryptoorystalline to fine trschytic (4 mm. long).
lduch of the rock shows trachytio texture.
Interest oenters on the structure shown by the exposures. In essence the
struoture shms rsperted brscciation, repeated intrusion ad welding accompanied
by rather strong flowage, The mineral composition of the succsssive inwelling8
of igneous material is not oonstaot. Especially does it shm variation in mafic
content. Similarly the textural diffursnoee of the successive imellings show con-
siderable variation in grain size. The coarsest material seen is also the most
quartzose -- essentially a grsnite.
In ma, Seo. 28, TZSH, R7E. dong the east-west road whioh has been
oomparatiwly recently cmr8truoted them is a large mowt of float material that
has been dug up by ths eonstnation oms and tossed aaide. Outcrops are few here
but tho float is so plentiful md i8 80 oomistsntly eplite urd it8 phases that
the inforrntion fielded is of interest. Southwerd near the Big Rib River, in the

lcnolands. the rook is ccarse enough in teature to be grenitio and oarties 5% or
mom of quartz, though it i s essooiated closely vlth definitsly aplitic rock.
These lor3and ccourrenoea also show more highly mafio eyenitatsend aplite,~being as
high an 16% in mafio constituents. Northward the aplite becmea more truly aplitic
in texture, tbs awrage grain size decreesing nnr"3mard from 1+ mm. to well below
1 mn. KaMo conatituenta and quartz are b&h less prominent aad on the east west
rosd (north border of See. 28), the quartz is almost entirely missing. The rock
is therefore about 9s feldspar a d $ or tetr mafio 5tsr-Sel.
The aplite here carries inolusions of quartzite and of modified greenstone-
like material. The quartzite inclusions are elongate but appear to be little
altered. The mafic inclusions are augen-like in shape and are aligned with the
structure ofthe rock. The rock as a whole is intensely and finely banded, the
banding being most commonly arident in the seleotive aligmnent of discrete mfio
constituents. Ilmver, where ths rock is essentially pum ieldspar ard the banding
is not at all evident on a fresh break, the weathered ruriace usually reveals the
fine banded stmoturn.
A peculiar feature of the banding is that it ia not by any means parallel,
except ovsr a distance of a foot or less. Extreme departures from parallelism
appear almost lfke cross bedding.
In places, large (one inch) pegmatoid orthoolsse crystels are developed in
the aplite. Agrin, narrow (1/4 inch) indefinitely bounded dikes of syenite cut the
aplite dth an irregular trend. Since the aplite ia here consistently acme shade
of red or pink and these dikelets am also pink, the blending is emphasized. A
few ooerse (6 m.) gray hornblende ayenite dikes of 1-4 inches cut the aplite in
this vicinity.
In the same locality them is float of nepheline syenite indiceting quite
surely that at least one nspheline syenite body also outs the splite as does ths
gray hoznblende syenite, but none %s fo-6 doing so in the float.
Distinctly porphyroblastic aplite is a rather common type of the aplite
area in T29N. BEE. It is composed of about 2% quarts and 15-2& biotite; the re-
minder is feldspar. The feldsper is in part present as pcikilitic, subhedral
porphyroblasts in a matrix of cateclastic, brownish oligoclme, or.thoclase sad
quartz. Tho biotite is largely in aggregates.
The aplite in places appears to be derived from a hybrid magma. To mention
one of these the aplite in SW4, Seo. 26, T29N, R6E, is composed of feldspar
75-9%, quartz SIC$, md amphibole and chlorite 2-1@. It is not uniform, as the
above percentages indicate, but is massive or goeissic, uncontamineted or zenolithic,
or cut by pegmatoid dikes. The aplite in general is inclined to be more rmfio,
some of it much mom mafic contiguous to the greenstone which it intrudes.
Fib*
Although the syenites oocur mly in comparatively nar.rm dikes,
neverthe 0s-y outcrop well and are availeble for. study. The syenitss occur in
e great many varieties of color and oompos$tton and textures. The most cornon of
811 the syenites is the gray, the most striking is the pink, and both have wry
apeotacular phases of syenite pepatits. there ths pink syenite contacts the gmy,
intrusively. the gray is conuertsd to a brvan syenite which should not therefore
be regarded 6s a distinct rock type. The gray syanite is quarried in tFio places
where it ia tkrefore well exposed. Although it is simj lar wherever found, the

follMng descriptions are quoted from the field notes on the quarries which are
in neighboring dikes and are only 1/4 lnile apart.
One quarry is ia XI:, Sec. 23, 22911, R6E, and is reached from County Tnmk
Bigbay "U." This is dark gray spnite oampcsed of an estimstsd 8% orthoclase
and 16% mphibole. The texture is messive. granitio (4-6 nan.). The quarry rock
is out by two distinct types of peptite and a highly mfic aplite. Bo Ism-
prophyrsa am seen. The earlier of the peginatites is dark, the same oolor as the
host, and is composed of an orthoclase, tke moonstone variety, in crystals usually
under 5 inches long, associated with black amphibole crystals which are usually
smaller than the feldspars. The later pegmatite is composed of light-colored
orthoclase in crystals up to 18 inches long, associated with bleck amphibole
crystals wkich are very elongate, up to 12 inches long, 5d usually under 1 inch
wide. These psgmatite dikes are of wrious thicknesses, commonly 4-6 inches, but
mnge up to 2 feet thick.
The other quarry is in SE~ Sec. 14, T298, R6E, and is also reaohed fram
County Trunk Highy "U." The spnite here is si&lar to that of the south quarry.
The pegmatites in it are larger and more numerous but are otherwise similar. A
special feature of this quarry rock merits desoription. There are in it ares8
from 2 feet to 10 feet across of mafic syenite (shcnkinite). Its composition is orthoclase 6%. amphibole 3%. and biotite 10gb. The biotite is in both smll
flak-es and in 1 inch poikilitic phenocrysts. The orthoclase is dark and with the
anphibole occurs in 2-5 m. crystals. This rock makes rather sharp angular contact
with the gray syenite host. Also evident in the gray syenite is a smaller -
6 inch to 1 foot - mcttling which shows up as a faint gray color contrast, the
affect being that of a ghost iepeoua breccia. The host is slightly lighter gray
in color. The mineral composition is the same so far as can be told.
In N E Sso. ~ 52, T298, R7E, is a large disintegrated syenitb pit. In this
pit am exposed several varieties of ruck, most of whioh am eyenite. Them are
several outcrops in th5 tri=-gdar area betnasii Xghvsy 29. the sldo road and the
river. The area is one of syenite mainly.
Although there are several varieties of rock present, most of them are
syenitic, end most of them are coarse, granitic in texture. hch of the syenite
is messivs, but same is gneissic, the gneissosity being of the ortho type rather
than of the banded type. At one point there is a dike of fine-grained grnnite
cutting the syenite; it is 6-10 feet thiok. The syenite, and the granite too,
haw strongly aplitio phases, rhich grade into the coarse granitio phnces and have
apparently the same mineral composition as the rocks in which they occur. In the
syenite the aplitic phases appear as locel areas surrounded by the coarse granitis-
textured host. In the granite the aplite appears as indefinitely bounded dikes
in the host.
The main syenite is composed of per%hite estimated at 8% and black
amphibole 1%. The texture is cosrse, 8,-10 m. for the feldspar, nnd about half
tkt for the mphibole. The syenite splits is fine textured (under 1 m.) and
equigrenular. It has gradational boundaries with the spnitc. In places at
these boundaries there are mafic aggregates 1-2 om. in diameter..
Anothsr phase of the syenite maa found at the pit. It is coarse granitic
in texture (6-8 mm.) and is composed of feldspar estimated at 80d@ slld mafics
st 15$. The feldspar is extremely finely twinned, evident only under 16X mag,-,
nirication. The amphibole is black, and is poikilitic. Inclusions in it are

mainly felZspar and a little magnetite. It oocura in grains equivalent in sim
to those of the feldspar. There ic present ezl oocesional grain of quartz. The
oolor of the rock is gray with A faint pink shade.
Still another phase of the syenite here has a strong red oolor. Its tex-
ture is sMlar to that of the syenite just desoribed but it appears to contain
orthoolase instead of plagioclase. It has about 8096 feldspar. 1% bleok amphibole
snd a small smount, leas than 6%. of quartz. The feldspar is very oonsistently
twinned on the carlabad law.
It will b shm later that the syenite dikes are composite and are mutually
independent. The variations therefore are potentially innumerable. The desoriptions
given a6ms are consicbred adequate for the present purpose.
2- He heline syenite. - There are many dikes of nepheline Byenite in the area.
almost as many in faot as there are of syenite. Two types of nepheline syenite
occur the most frequently. They are quite similar except for the oolor of the
nepheline which thgroontain. Ye refer to the one as the gray nep'helins syenite
and to tb other as the pink nepheline ayenite.
The hest exposure of the gray nepheline syenite is to be found in a hill
with good outcrops in SE~ Sec. 2, T29N, R6E. This rock is very slightly gneissio,
so slightly so that a determination of the attitude of the gneiasosity is sometimes
difficult. It is otherrriae massive, medium textured (3-4 nun.) and granitic. It
is composed of nepheline end feldspr about 8C$ and black amphibole 2C$. The feldspar
and nepheline are present in about equal quantities. The strong pitting of
the reathered surfeoe is invariably tb best indication of the amount of nepheline
premnt sinw on the fresh break the nepheline and the feldapar ere much alike.
The nepheline and the feldspar both are medium to dark gray in color. Ho white
nepheline was seen in this rook anywhere in the area.
The pink nepheline syenite occurs in many places in the area but n h r e
in prominent outorop as does the gray. It is usually gieiasic and comody ~ei--
strongly so. Its color is some shade of red or reddish brown. The feldspar which
is tabular and which by its aligmnent creates the gneissosity my be white, gray
or also pink. These tabular feldspars may Im 48 mm. long in the typical rwk.
The texture is intersertal, the nepheline being the last to orystallize. The
mpheline in this rook is rather riohly colored, a light to dark reddish brown.
This rock may be studied best in float along the south border of Sac. 1, T29N.
R6E.
syenite pegmatite. There are two places, or possibly three,
where th ?@line s rook occurs, though in both it can scarcely be termed a syenite. Pegmatite
solutions from the nepheline syenite alone seem able to penetrate the overlying
greenstone (~r~i1lit.e). and where they do the reaction produces a very coarse
dark green, ptygmatically folded injection gneiss. These two places are (1) from
the midpoint of the south border of Seo. 22, T29N. R6E to the nest quar.ter comer
on the south border of See. 23 contiguous to it; (2) in the SF$ W& Sec. 18, T29N,
WE, and in the vicinityj (5) the third locality is in RE; S E Seo. ~ 21, TZBN, R8E.
It is apparently similar to the other but is very poorly revealed for study.
At tb first loca'lity the nepheline penetrates the greenstone as a eissic
injection. The pwtr.ation increases in degree and coarseness to the sect on
corner. The rock is a dark, ptygmatically folded amphibole and chlor,ite gneies
consisting of a host of feldspar about 4G, mafica 3% and quartz 5%. In this rock
F

the pspatite both orosses the gneissosity and follows it, eiving local pookets
and narrow stringers. Single crystals of feldspar and nepheline measure up to 6
inches long and commonly up to 4 inches long. The feldspr is white, the nepheline
is brownish.
At th eecond locality, also penetrating the greeristone, is a large amounr
of high nepheline syenite and apparent nephelinite. The nepheline is quite distinctly
reddish end oarriee lb1$ of mfioa. It appears in peissio form, some
bands bing very aplitic nephelinits and nepheline syenite and some being quite
peptoid. The nspheline-bearing rocks are quite dark greenish despite the reddish
cast to the nepheline under the lens. At the western end the float indicates a
greenstone breccia penetrated by nepheline syenite pegmatite as host. The fragments
are large and small. They are chloritieed heavily and we11 digested by the
pegmatite. The pgre~tite is composed of dark red4ish nepheline 70-@ and orthoclase
SO-%. No twinning is evident in the feldspar. The crystal size of the
pegmatite is up to 2 inches.
mite Nepheline S nite This rock is separately treated because its
i y It was dstaken for sli~htlv feldspathic nephelinite
in the field butis fc&d in the laboratory to be cmposed of about 265
nepheline only, the remainder being black =.phibole 2% and feldspar 66. The
feldspar is plagioolase and perthite, of good white color. The perthite 5s wall
orushed though considerably recrystallized, whioh gives it somewhat the appearance
of nepheline in the field.
Cdbr is of marketable qaa 3-e
- -
There are three occurrences of this white nepheline ayenite in the area
so far as horn but there are undoubtedly others not yst discovered. One is men-
tioned in the Last section, though this is the leaet spectacular of the three.
A seccnd ooourienoe is that of two white nepline syenite dikes in the floor of
a disintegrated nepheline syenite pit in Im, Seo. 1, T29N, R6E. These are poorly
sxpoaed but the pit contains several residual boulders of the rock. The third
and best is in NE$ SP~: Seo. 5, T29N, RE. Here the syenite oocurs in a dike 150
feet wide so far as can be seen in the weathered pit. Both the nepheline and
feldspar are quite white. The texture is granoblastio.
Struoture. Later granitic intrusion has so thoroughly meshed the clder
foxmations thst the section is and will doubtless remain l~rpely unknown. Among
the oldest rocks of the area probably are the rhyolites. Sinoe they are not
eveqwhere intensely folded, and since they predominate mong the volcanic8 of
the area--in feot, basaltic greenstone is extremely rare-one develope a feeling
in the field th~t tbse rocks are not pre-Huronian but younger. On the other
hand the rhyolites are rather consistently folded on an axis whioh trecds slightly
north of east indicating one time shor.tening from the north and south, uhereas ths
later regional shortening is from the east and vest. Som of the argii.lite and
some of the quartzite is only slightly folded, indicating that folding is not
uniform within the area. Some rhyolite, too, shows little evidellce of being
folded, indicating that the folding is localieed within the area. One po~sibility
not to be discarded is that there are both pr,e-Huronian rhyolites and ieter
rhyolite and argi1:lite. The occurrenoe of tuff and agglomerate with and in the
argillite suggests strongly a rhyolite association. But the occurrenoe of
argillite in very slightly disturbed attitude fkvors setting it aside from that
part of the rhyolite which is so closely and uniformly folded. Although this
question is too apeculetive to answer, it seems most nearly answered by this
last suggestion.
As far as is known then, the section consists of rhyolites, folded find
intruded or not, overlain by srgillite, and possibly rhyolite of later age, and

these overlain by quaxt~ite. The area was then folded and intruded by granites
which may be of Keweenawan age, though this age too is quite unknown. Toward the
olose of intrusion by this granite whioh appears to be the main granite of the
area, rotational pressure frm 5e east and nest oauaed mild fauZting with asso-
oiated dike mriplacement giving the syenitee of various types.
The granite intrusive in this area has a very flat roof whioh elmost coin-
oidea vith the present erosion surface. Slight irregular.ities in the roof inter-
sect the present surfaoe, giving alternately areas of granite and roof pendants
in the granite. The map area is located nrithin a large group of such roof pendants.
Cupolas of the granite have penetrated the roof in many places and have been
truncated by erosion. V,here penetration and subsequent erosion are deep, the
granite is the norm1 red type of the eraa, but there are three large dome-shaped
cupolas which have been only slightly truncated. These ara the three areas of
aplite already deaoribed.
There is good evidenoe that the lower surface of the various roof pendants
is also quite flat and always 0108s to the present erosion surface. Near to and
betasen any two bodies of greenstone, the granite is charged with inclusions or
is contaminsted Kith mafic material or even is a granite hybrld. Using this type
of information and applfing it in a rrertical section we have been able to arrive
at an approximate figure of the angle of inclination of the lower surface of the
pendant, it is 5 degrees, an average figure. This is well supported by the mapped
greenstone capping of the hills in Sections 21, 22, 27, 28 of T29N, R8E. and in
Sections 7. 18. 19 of T29N, R7E. Kith the exception of the granite, therefore,
all rook types within the area nay be assumed to be shallow, to give way to
granite at comparatively shallow depth.
The shortening in the east-west direction is expressed in more than one
my. The overlying quartzite was folded along a north-south axis with minor warp-
ing in an eaat-west direction. Along the present course of the Big Rib River
the quartzite mptured, doubtless due to wenkening by the subjacent intru~ive
dome, a d a iarge block of tne quartzite, disengaged from the mein body, essen-
tially floating on the intntsion, and was rotated, as apparently was the quartzite
at Ablemens, F;'Ssconain, under the influence of displaced material in the tr.ough of.
the closing north-south fold. This block now stands up on edge to form Rib
Mountain, giving the false impression of a fold vith a 90' pitch. The limbs ere
seen in the Mosinee Hills end in Hsrdwood Hill. Huwever, we are interested in
that aspect of the structure here only in its relationship to the local structure.
The quartzite of Rib Hill has served as a buttress to the east-vest shortening
and has given it a strong rotational component in most of the map area. The two
shear planes developed as a consequence of this shortening are: (1) the rhyolite
bedding faults whioh strike N 80' E and dip 80' S. Such bedding faults char.acter-
istically have dissipated mowmnt thr.ough the bedding and though characterized
by muoh movement reveal little of it. The shearing only indicates that movement
in this area3 (2) the fault planes which strike N 20° E and dip steeply. The
elongation bisects the angle and is then N 50° E and the greatest shortening is
to it. - N 40° W, This last is the strike too of the consequent tension p?aneS.
end *his is expressed by the syenite dikes.
Along none of the faults of the area is there nny great movement. In
fact, the movement is little more than taken movement. Hmever, the faulting is
very well expressed in the topography of the area and in the stream pattern. Uost
ofthe dikes, and doubtless all of them aie characterieed by some move~ent betmeen
their walls but very few of them shm enough movenent to cause the elinination,

or other modification in mapping, of the exposed formations. Scms ruch evidence
of movement is found along the south border of Seo. 22, T29N, R6E, where the
aplite which forms a selvage between the greenstone and the ayenitio rocks within
the aplite at' almost all places, is faulted out. But bstter evidenoa of movement
along the dike-filled feults is to bs seen by follming the trpnd of the dike beyond
the limits of the dike where there are invariably such aigns of faulting as,
sheering to produce a sohist, or fault gouge and mylonitisation or spectacuLar
brecciation. Som of these are described by r,@:aib. A few oacurrences may b
mentionedr (1) Fault gouge in the extreme northeast corner of Sec. 17, T29N,
R6E; this is developed in graenstonej (2) Rhite sericite schist developed in the
aplit~ in,& S E Sec. ~ 8, T29N, R7E; (5) Tyhite sericite schist dewloped in rhyolite
in ST:* SET Sec. 26, T3011, R6E; (4) Intrusive greenstone breccia in SY;* S E Sac, ~ 9,
T29N. R6E; (5 Another in SY,$ Sec. 18, T29NJ R7E; (6) Another in SE$ S E Sec. ~ 26,
T29I7, R6E (7 Sheared and shattered quarttitic argillite in a weathered roadside
pit in Sz i Sec. 16, T29N, R6E.
There is abundent eviderioe that- of the dikes are composite. Their
em laoemsnt history is threfore one of intermittent opening and filling, dth or
wi F: hout dieplacenent along the fractures. The most common of the dike rocks is
the gray syenite. &xt most common is perhaps the red and pink syenite. And
next am the gray nepheline syenite and the red nepheline syenite. There are many
other syenitic typea. None of the dikes is large; most of them are quite smell.
All an, very looal ?ad give evidence not only of having originated locally but
definite evidence that the dike magme did not travel far. For instance, the margin
of the aplite, near the greenstone is rarely cut and the greenstone is still more
~rrely cut, though both are sheared and bmooleted, and when out it is by only the
more mobile peptitio solutions.
Afthoughwe have mapped 67 dikes, the correot number is doubtless cloaer
to 200, and if single emplaceme&s ere counted as separhte dikes, esch dike must bs
regarded as not less than 5 and probably 10 or 20 dikes. This is most convinc-
ingly illustrated in the pit and adjacent brritory of hVi2 13,; Seo. 52, T29N. R7E.
----
Pstrogeny of the aplite and syenites. This will be discussed elsewhere
after ad=;telaboratorystudy.
Economi=olo (1) Re heline. Our petrogenic conoluslons whioh are
not er,guxz aredzthe apde, the syonite and the nephellne syenite are 0f
strictly local origin, developed from the rocks in which they occur. Only the
nepheline syenite pegmatite is sufficiently mobile to penetrate beyond its point
of origin and enter the overlying rocks. the greenstone. Therefore the aepheline
is to be sought aithin the aplitic areaa, in those parts of the aplitic areaa
which are faulted and only along the fault lines. Attention has been called to
the irregularity of composition of the aplite from which the syenites are derived.
The syenites take on the character of the aplites in which they occur. &here the
aplite carries free quartz, the syenites also are quar-tx syenites. But Bore im-
portant, where the aplites are mafic, the syenites are mefic and when the 8y?nite
is nepheline bearing some of the iron is found in solution in the nepheline. Since
onerequirement of commercial nepheline is thet it be ircn fme or lm in ircn, tho
search can be very materially aided by more detailed mapping of tb aplite.
Specifically, the search should be for a truly ayenitic eplite and one which is white,
There is one rock in the area which offers real promise of yieldlng gyod
comnercial feldspar and nepheline, that is the white hornblende syenite in KV,; SY.,
Sec. 5, T29N, R7E. This rock cpm be studied eesily in the leboratory for sepKr0-
tion of the mphibole. Mepetic aeparaticn should be adequate. The host to the

amphibole is: qu5te white. The site of the dike is not known but if the sample
proves encou'raging, the tonnage can be easily determined by drilling.
.
Aside from the occurrences of white nepheline syenite described, no white
nepheline was seen in this study.
(2) Zircon. Ziroon is found in quartt veins in one locality only, Seo. 22,
T29N, R6E, but my well oocur along any of tha nor-thmst faults nhich we have
mapped. This one occurrence is so far unique in the area. Along the fault the
underlying granite -- parent of the aplite - has penetrated more extensively than
it is known to hsse penetrated along the other faults. Even this penetration is
mostly by the more mobile granitic pegmatite juices. In other words, this is tb
uppermost tip of a granitic tongue and must necessarily enlarge downward. It is
to be expected that the siroon content of the ore body will also improve with
depth despite the fact that the ore is primarily in quartz veins.
It is rholly reasonable to believe thst the ultimate parent of all thsse
varied rocks within the eplitic area is the same granite. Themfore it may be
suggested tbt further prospecting for zircon may be guided by the search for coarse
feldspathic pegmetits such as that seen in Sec. 22, T29N, R6E. The less prodnent
quartz veins may then be sought in and around the pegmatite.
S ) t e . A S x 4 foot boulder of yelloaish pyrophyllite was found
in NV!~ Sec. , d9N, R6F. The boulder is composed of massive pyrophyllite and
quartz in which are grown radial pyrophyll5te crystals. A part of the boulder
contains about lU$ of quartt grains. The mineral is undoubtedly of good oom.ercia1
quality though not the best quality,
Inquir revealed that this boulaerwas dug in SE: Sec. 28, T29N, R6E, and
hauled may. $he area is now a cornfield. without rock exposures. It is highly
probable that this mineral is cf local occurrence and should be further in~estigated.
The -r of the land is Mr. F. E. Mearek, R.R. 2, Earethon, Tisconsin.
(4) Disintegrated "granite." Throughout the entire ares rs have observed
that disintegration of tK8rock by neatbring is ad~anced sufficiently for explcitstion
for road materials only along the fsult tones. Not all the faults have
been recognized but more can be estimsted with fair reliability from the evidence
that has been cited and promising areas thereby may be located for roahaterieis.
Anotbr pertinent suggestion may be made for locating faults nnd there-
fore disintegrated granite within the grenite areas. Pe have observed thst the
diaintegration of granite along these faults yielas as a by-product a profusion
of large, glacial appearing boulders. Norm1 aeatherlng also produces boulders
of this type but not in profusion. It is auggestad that an examination of aelial
photographs may yield useful information of this type.
--
Rec~~eniations. It appears desirable to obtain more detailed information
on this 'promising area than ne have been abh to gather in the four weeks st our
disposal. It is suggested that a party be sent in for a full smer to map, on a
scele of 6 ixhes to the mile, the area of gr.satest promise around Stettin. Search
should be made for. (1) white syenite aplite; (2 ranite or syenite pegnetite of
the type found in that Redant zircon property; white hornblende syenite; (4)
pyrophyllite. This eaale Kill pernit the mepping of the a~enitic bodies on a true
dimension basis rather than on an exeggerated scale, as is done on the accompan~in~

map. Alao, them is much information to obtained by oowrlng the areas mithin
critical sections rather than only the area adjacent to ths highways to which n
haps neoessarily ban limited. Also, the three tomships in soutmRest corner of
the pressnt aap area which rrs have been unable to do in the tims at our disposal
could be done on a reconnaissance basis, as has been dons elbewhere in the area.