Mineral Industries and Geology of Certain Areas - Vermont Agency ...

26 REPORT OF THE VERMONT STATE GEOLOGIST.
REPORT OF THE VERMONT STATE GEOLOGIST
27
line. The more special field of exploration was the part of the
limestone region lying between Rutland and Monkton north
and south and the adjoining region reaching westward to Lake
Champlain. The crystalline limestone of the Otter valley had
in the Vermont geological report of Hitchcock been designated
as the Eolian limestone."
This limestone, this " Eolian," with its sandstone beneath
and its slates above; what its geologic age? This was the
question which Mr. \Ving asked and vhich he set himself resoluteiv
to answer.
The task for one of Mr. Wing's surrotindings was immense.
The problem was intricate and one that took years to solve.
In the solution appeal must he macic to the rocks themselves.
It is asserted that the feet of this explorer have stood UPOfl
every square rod of exposed rock within the region of his survev.
The lithological character of the rocks, their dip, their
order, their fossil contents, all must be known. He carefulIr
noted the superposition of the rocks, measured the dip with a
clinometer of his own construction, and sought with wonderfully
observant eves for traces of fossils.
The rocks of this region had been so folded, broken and
worn that at first their true position was uncertain. The fossils,
too, in the partly metamorphosed rocks were mostly faded
and obscure; their identification difficult. But as the secret of
the age of the formation must be unlocked by these fossils, this
key was most carefully and in time successfully sought. Many
of these fossils Mr. Wing himself determined, but for verification
and in cases of doubt he turned to Mr. Billings, of the
Canadian geological survey, from whom he received courteous
attention and generous help.
So the search went on for years, summer and winter, holidays
and vacations. Holidays gave Mr. Wing opportunitY for investigating
the near-by rocks, vacations afforded him time to
visit far-away places in the State Or in adjoining states, whereever
he hoped he might g -et light upon his problem. It was
as thong-h he were working- at a broken and tangled skein. By
study of the composition of the rocks, by the use of the clinometer,
but above all by the careful comparison of fossils, he
disentangled the knotted, broken skein and by placing the
separate threads beside each other, he arrived at a knowledge
of the true relation of thread with thread; he determined the
right order, the real sequence of the rocks. His problem was
solved!
The problem: the age of the limestoneS of the Otter valley,
with the associated sandstones and slates. The rocks were
those designated Lower Silurian; the sandstones were the
Lower and Upper Potsdam, the semi_cryStalhilw limestone, the
Eolian." was not a single formation, but was made up of rocks
of the age of the fossiliferous formations along the lake shore,
now known as Beekmantowll, Chazy, Black River and Trento1
the slates were mostly the Utica slate, lying in many cases confori
-nably above the Trenton limestone.
So the views of Mr. Wing may be fairly expressed in a few
words. The limestone region of the Otter valley lies within
a great svncline. On the east it is bordered essentially by
ridges of quartzyte, which extend aloog the western foot of the
Green Mountains; on the west by the red sand rock vhose elevation
and fracture forms the great fault north afl(l south, seven
to nine miles from the Champlain shore. The axis of this syndine
descends southward, while on the north it rises until the
worn rims of the siliceous rocks, the quartzyte and red sand
rock very nearly approach and unite. Within this trough lie
the himestones and slates. These are of the age of those that
lie west of the great fault, the fossils of which long ago placed
them with the Lower Silurian. These strata, originally de-
0untain_making
posited in regular order by some grand
rnovement. have been folded, compressed, snapped and displaced;
the fossils by the same movement largely obliterated.
The great syncline was left with subordinate north and south
anticlinals and synclinals the whole complex was exposed to
the subsequent abrasions of geologic time.
It was the planing down and the enormous
wastage fro m