273 
NOTES ON SPECIMENS OF CEPHALOPODA 
FIGURED IN TATE AND BLAKE’S 
‘YORKSHIRE LIAS,’ 1876. 
BY THE LATE GEORGE C. CRICK, A.R.S.M., F.G.S. 
At the end (p. xii.) of the ‘ Explanation of the Plates/ in 
Tate and Blake's ‘ Yorkshire Lias,' 1876, occurs the following 
note : — f The greater number of fossils figured in these plates, 
where not otherwise specified, are in the Museum of Practical 
Geology, Jermyn Street.' In carefully working through the 
J. F. Blake collection acquired by the Trustees of the British 
Museum, one was therefore somewhat surprised to find in 
that collection a number of the Cephalopoda which were 
figured in that work. The following notes relate to the 
identification of these specimens. 
The systematic position of the figured examples is not 
discussed here. 
Ammonitid^e (p. 261). 
Mgocevas planorbis J. de C. Sowerby sp. (p. 270). 
Blake observes (p. 270) : ‘ The flattened specimens obtained from the 
clays of Cliff agree with Sowerby’s type, as do those in the Eston gypsum 
pit, but the more perfect specimens, which are obtained from blocks of 
limestones washed up by the sea, and which have long been known under 
the local name of A. erugatus, are a little less involute.’ The Blake 
collection includes a flattened, obscure specimen about 43 mm. in 
diameter exposed on the surface of a piece of clay [B.M. No. C. 19209] and 
unfortunately is unaccompanied by any information. Though flattened 
like the Watchet specimens, it is of a brownish colour and exhibits no 
iridescence. It is possible that this is an example of the species from the 
clays of Cliff. The collection contains also a sub-triangular fragment 
(about 90 mm. by 75 mm.) of a water-worn block of limestone, such as 
is mentioned by Blake, exhibiting on its fractured surfaces a number of 
examples of ‘ Ammonites erugatus ’ [B.M. No. C. 19176-82], the largest 
example having a diameter of about 42 mm. Unfortunately the fragment 
is not localised. Blake states : — ‘ Two varieties are found in Yorkshire 
and elsewhere (corresponding to the A . psilonotus Icevis and A . p. plicatus, 
of Quenstedt), one smooth and the other with light bent ribs.’ Both 
forms appear to be represented in the block. There is also in the collection 
a detached example of the species, 31 mm. in diameter, that has been 
mesi ally sectioned, but it is not localised [B.M. No. C. 19175]. 
Mgocevas johnstoni J. de C. Sowerby sp. (p. 271). 
The Blake collection contains no specimen so labelled. 
Mgocevas angulatum Schlotheim sp. (p. 271). 
Blake did not figure any example of this species. He states : — 
* There are two varieties : (a) most involute, the outer whorl being 
more than \ the diameter — the common Redcar fossil ; ( b ) less involute, 
with outer whorl \ the diameter, occurring chiefly in the southern area.’ 
His collection contains an example 45-7 mm. in diameter [B.M. No. C. 
18110], labelled in his own handwriting : ‘ A angulatus, Redcar * ; 
also another smaller specimen 50-5 mm. in diameter [B.M. No. C. 
18111], not labelled, but appearing from its matrix to come from the 
same locality. 
1922 Aug. -Sept. 
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