74 
JURASSIC, OR 
JURASSIC ROCKS. 
CEPHALOPODA. 
By Professor H. F. Blanforij, 
OF CALCUTTA. 
The Jurassic Cephalopoda, described in the following 1 pages, 
consist of 19 species: one of which is a Belemnite, the re¬ 
mainder Ammonites. The single species of the former genus 
is certainly identical with that previously described from 
Cutch and the Oolites of the Spiti Valley, and the differences 
which distinguish it from the B. sulcatus of Miller are so 
slight that I cannot at present regard it as specifically distinct. 
Of the Ammonites, two species only are common to the 
Oolites of Cutch, viz., A. biplex, Sow., and A. torquatus, Sow., 
but the same two species, together with five others, or nearly 
two-fifths of the entire number, exist in the Spiti collection of 
Dr. Gerard. Of the Liassic European Ammonites figured by 
Mr. Everest, and on his authority described by myself as 
forming part of Gerard's collection, not one occurs in Colonel 
Strachey's cabinet, and I have now strong reasons for be¬ 
lieving that their intermixture with the Spiti fossils was ac¬ 
cidental, and that the specimens in question were really from 
the alum shale of Yorkshire. Except A. biplex, Sow., and 
A. triplicatus , Sow., no well-identified European species occurs 
among Colonel Strachey's fossils, but many of the latter are 
closely allied to European types, and of these almost exclu¬ 
sively to Ammonites of the Oxford clay. Some of the species, 
indeed, A. jubar , and A. Griffithii , Strachey, for example, are 
but doubtfully separable from European forms. 
The majority of the species belong to the section “ Ornatl” of 
Von Bueh, but there are representatives of most of the other 
Oxfordian types, as will be seen by the following classified list:— 
Fimbriati . A. alatus. Stracliey. 
Macrocephali A. Ncpalensis. Gray. 
Coronarii . A. umbo. Strachey. 
A. guttatus. Id. 
Planulati , A. biplex. Sow. 
A. triplicates. Sow. 
A. torquatus. Sow. 
A. scriptus. Strachey. 
A. tenuistriatus. Gray. 
Armati . . A. jubar. Strachey. 
Ornati . . A. octagonus. Id. 
A. Hoolccri. Id. 
A. Medea. Id. 
A. Wallichii. Id. 
A. robustus. Id. 
A . Griffithii. Id. 
Amalthei . A. slrigilis. Blanford. 
. ? . . A. acucinctus. Strachey. 
