Arkell.1956.Jurassic..

KARAKORUM
series of major expeditions, to whose collecting we owe what little is
known. The first to bring back Jurassic fossils was the de Filippi expedition
of 1913-14, which crossed the Karakorum Pass and descended into the
Tarim basin, returning by way of Yarkand, Kashgar and Tashkent. A
vivid idea of the country may be obtained from the first-rate description
and hundreds of superlative photographs (de Filippi, 1932). From a
small valley, tributary to the Shyok River, immediately south of the
Karakorum Pass, about 125 specimens of ammonites were collected from
a marly limestone. They are mostly fragments and the preservation is
poor, but they suffice to identify the Anceps Zone of the Middle Callovian
(Stefanini, 1928). With them occur foraminifera and a cosmopolitan
assemblage of pelecypods—Chlamys, Lima, Ctenostreon, Pholadomya,
Goniomya, Oxytoma, some Rhynchonellids and Terebratulids, foraminifera
and sponge spicules. The locality was called the Valley of Ammonites.
The assemblage of fragments figured by Stefanini comprises Grossouvria,
Choffatia, Reineckeia, Oxycerites and Hecticoceras, and is unmistakably
the same as that known from Lake Urmia and the Elburz Mountains of
north Persia (see pp. 366, 370). In particular, Hecticoceras (Brightia)
aff. metomphalum Bonarelli and H. (Putealiceras) paulowi Tsyt. occur in
all three areas. Like the Lower Bathonian of the Pamirs, this fauna seems
to demand a seaway across Bokhara from the north-eastern Elburz. (With
Spath (1933, p. 806) I would reject Stefanini's identifications of Kosmoceras
(pi. viii, fig. 5), Villanya (pi. xi, fig. 4), and the rolled fragment of a (Spiti
Shale?) Perisphinctid (pi. x, fig. 4)). Four more Pseudoperisphinctinae
from the same locality have since been figured (Frebold in Norin, 1946,
p. 196, pi. xxii: fig. 4, Choffatia sp.; fig. 5, Poculisphinctes sp.; fig. 6,
Indosphinctes sp.; fig. 7, Grossouvria sp.).
The Trinkler expedition of 1927-28, following an earlier synthesis of the
Himalayas sensu lato (Trinkler, 1922), produced another great work on
the Karakorum and Kuen Lun (de Terra, 1932). No Jurassic ammonites
were found, but from near longitude 78 0
a small assemblage of pelecypods
in a neritic broken-shell limestone includes Variamussiumpumilum (Lam.),
Camptonectes lens (Sow.), Pseudolimea duplicata (Sow.), Ostrea calceola
Zieten, Trigonia formosa Lycett and other common European species, and
seems to indicate Bajocian (Staesche in de Terra, 1932, p. 145, pis. xxi,
xxii).
In the Aghil ranges, about 40 miles north-west of the Karakorum
Pass, Mason (1928, pp. 97-8) found Spiticeras aff. scripta (Strachey),
S. spitiense (Blanford) and Virgatosphinctes aff. denseplicatus (Waagen),
which proves that at least the middle and upper faunas of the Spiti Shales
are represented.
Since three expeditions have all found different faunas, it is evident
that these mountains may still have many Jurassic surprises in store.
http://jurassic.ru/