Cephalopoda in Tate and Blake' s ‘ Yorkshire Lias.’ 277 
the original of his PI. VII., figs, ia, ib, although it bears no label or any 
marks whatever. The displaced position of the anterior part of the 
specimen — the displaced portion being the base of the body-chamber — 
serves at once to identify the fossil, although an obvious irregularity 
in the curvature of the whorls is not indicated. The figure is reduced ; 
the greatest diameter of the fossil, that is at the extremity of the septated 
portion, being 58.4 mm. Respecting the ' Geological position ’ of the 
species Blake writes : ‘ Zone of A. oxynotus. In almost every nodule 
of a certain band in the upper part of the zone at Robin Hood’s Bay, 
Londesborough. ’ From this statement it is clear that the fossil come from 
the zone of A . oxynotus, and it seems fairly safe to conclude that it was 
from Robin Hood’s Bay. It is accompanied by a loose label (which 
•cannot now be fitted on to the specimen) on which is written : PI. C, 
fig. 1.’ 
There is, in the Blake collection, a small rock-fragment containing 
two individuals. The fragment [B.M. No. C. 18123] is labelled in Blake’s 
handwriting : ‘ A subplanicosta . L. Lias. R. Hood B.' Another fragment 
[B.M. No. C. 19207], containing a specimen 24 mm. in diameter, is 
labelled in Blake’s handwriting : ‘ Am. subplanic. L.L. R.H.B.’ These 
specimens appear to be what Blake regarded (p. 277) as the young of 
Simpson’s Ammonites obsoletus. 
AEgoceras armatum J. Sowerby sp. (p. 277). 
The ‘ Geological position ’ given by Blake for this species is : ‘ Sub- 
zone of A. armatus (characteristic), Robin Hood’s Bay, Warter, High 
Stones Redcar.’ His collection contains a number of armatus - like 
specimens but only two are localised. One of these [B.M. No. C. 19219], 
about 140 mm. in diameter, is labelled in Blake’s handwriting : 
‘ [Ammjonites [arm]atus [R.] Hood’s Bay.’ This seems to be referable to 
Simpson’s species A. miles. The other localised specimen [B.M. No. 
C. 19220] is an example 77 mm. in diameter, labelled in Blake’s hand- 
writing : ‘ Am. armatus Peak.’ As has already been stated in dealing 
with AEgoceras (?) raricostatum, the expression ‘Robin Hood’s Bay,’ 
given in the ‘ Geological position ’ of the species, would seem to include 
Peak at the southern end of the Bay. The collection includes a specimen 
[B.M. No. C. 19218], 19 mm. in diameter, unlocalised, but labelled in 
Blake’s handwriting : ‘ Amm. owenensis L. Lias ? ’ Blake regarded 
this species of Simpson’s as the young of Sowerby’s armatus. 
AEgoceras aculeatum Simpson sp. (p. 278). 
The original of Blake’s PI. VII., fig. 4 is in the Blake collection 
[B.M. No. C. 17878], the various fractures indicated in Blake’s figure 
rendering the identification of the specimen absolutely certain. Blake’s 
figure is reduced, the greatest diameter of the fossil being 104 mm. The 
specimen is labelled in Blake’s handwriting : ‘ PI. C., fig 4.’ It bears no 
locality label, but since for the ‘ Geological position ’ of the species 
Blake merely states : ‘ Sub-zone of A. armatus, Robin Hood’s Bay,’ 
this must be the horizon and locality of the figured example . The species 
is probably also represented by an unnamed specimen [B.M. No. C. 
18066], 92*4 mm. in diameter, marked in Blake’s handwriting : ‘A. Base 
of M.L. R.H.B.’ [ i.e ., Base of Middle Lias, Robin Hood’s Bay]. 
The Blake collection includes a specimen [B.M. No. C. 19221], 64-2 
mm. in diameter, labelled in Blake’s handwriting : ‘ Am. decussatus M.L. 
R.H.B.’ Blake regarded this species of Simpson’s as a synonym of the 
same author’s aculeatus . 
Another specimen in the same collection [B.M. No. C. 19222], without 
any label whatever, may be either an example of Simpson’s retusus, 
which Blake regarded as a synonym of the same author’s aculeatus, or 
of an allied species. 
1922 Aug.-Sept. 
