Arkell.1956.Jurassic..

250 THE IBERIAN PENINSULA
1933). From the Lower Bajocian there is a remarkable number of English
species of Haplopleuroceras, Graphoceratids and other ammonites as in
Morocco (e.g. Fallot, 1932, p. 55).
LIAS
All stages of the Lias except the Hettangian have been proved by
ammonites. A vast amount of detail is known and has been ably brought
together by Fallot (1932), but since the succession presents no special
novelties no attempt is made to summarize the data here. Fallot believes
that the original width of the Liassic sea between the Spanish Meseta
and the Sahara Platform has been nearly halved by tectonic compression.
He points out that the Lower Lias of the Betic Cordilleras does not differ
from that of the rest of Spain and much of North Africa, but that in the
Middle Lias (Cisneros, 1923, 1927) many peculiarly Italian ammonites
entered; and that, despite the especially Mediterranean facies (Ammonitico
rosso), the Upper Lias ammonites are those common almost all over
Europe. The presence of Middle Lias cherts in Sicily, the Subbetic
Cordillera and Gibraltar is noteworthy (Plate 10).
THE BALEARIC ISLANDS
A submarine ridge continues the line of the Betic Cordilleras into
the Mediterranean. Upon it stand the delectable islands of Majorca,
Minorca, Ibiza, Formentaria and Cabrera (fig. 24). Jurassic rocks occur
on all but Formentaria. By far the largest outcrops are those of Majorca,
but the succession is usefully supplemented by the other islands.
Structurally and stratigraphically the Balearics are a direct continuation
of the Betic Cordilleras, though a change of strike to N.-S. in Minorca
has given rise to much discussion (see Stille, 1930, 1934, 1937). The most
probable solution is that Ibiza and the main sierra of the north of Majorca,
in which the nappes are thrust to the north, belongs to the Subbetic,
while Minorca and the centre and south of Majorca belong to the Betic
(Fallot, 1945). The apparent westerly direction of the thrusting in Minorca
could be due to interference by transverse undulations, the easterly dip
of the thrust planes being merely off a culmination, as on the east of the
Sierra Nevada or the Malaga nappe. The outcropping of Palaeozoic
greywackes in Minorca and their occurrence as pebbles in a Burdigalian
conglomerate in the middle of Majorca, and the facies of the Mesozoic
rocks (which are not 'Andalusian' in Minorca and southern Majorca)
support this interpretation (Fallot, 1945).
In the Majorcan Sierra the Jurassic is as complete as in the Subbetic
of Andalusia and in the same facies (Fallot, 1922, 1931-4), but in Ibiza
the Lower and Middle Jurassic are absent and Upper Jurassic, beginning
with Upper Oxfordian, is transgressive on to Trias (Spiker & Haanstra,
1935). In Minorca no Jurassic ammonites have been found.
In the Majorcan Sierra the Lias begins with dolomites and dolomitic
limestones which pass up into massive limestones. An Arietites has been
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