2 j6 Cephalopoda in Tate and Blake's ‘ Yorkshire Lias.' 
Hood’s Bay, Warter and Market Weighton.’ As the specimen bears no- 
locality label, its ‘ Geological position ’ is somewhat uncertain, but it 
is highly probable that it came from the ‘ zone of A. oxynotus,’ Robin 
Hood’s Bay, of which zone, as Blake states, it is highly characteristic. 
The collection also includes six examples [B.M. Nos. C. 17884-8 and C. 
19191] ranging in diameter from 34.4 mm. to 17.6 mm. [C. 17884, 34-4 
mm. ; C. 17885, 30 mm. ; C. 17886, 25-2 mm. ; C. 17887, 23*3 mm. ; 
C. 17888, 19-0 mm. ; C. 19191, 17-6 mm.], each labelled in Blake’s 
handwriting as Ammonites gagateus from Robin Hood’s Bay, but the 
horizon is not given in any single instance. There are other examples 
in his collection but these are not localised. 
AEgoceras sagittarium Blake (p. 276). 
Blake states (p. 276) that ‘ the description and figure are taken 
from a specimen in the Cambridge Museum.’ This statement can only 
apply to fig. 2 a, as the original of fig. 2B is in the Blake collection 
[B.M. No. C( 17881]. It is a mere fragment of which only a portion is 
depicted and reduced (as shown by the thickness of the whorl) in Blake’s 
fig. 2B, but it is labelled in Blake’s handwriting : ‘ PI. C., fig. 2®.’ It 
is without a locality label, but as Blake (p. 276) only gives for the 
' Geological position ’ of the species : ‘ Zone of A. oxynotus (base), 
Robin Hood’s Bay.’ this may be safely regarded as the f Geological' 
position ’ of the figured specimens. The whole specimen consists of 
about one -third of a whorl from the base of the body-chamber forwards ; 
the length along the median line of the periphery being about 96 mm. 
The Blake collection contains another specimen [B.M. No. C. 18040] 
of about 145 mm. in diameter, consisting of a little more than a single- 
whorl, the inner whorls being entirely wanting. It is labelled in Blake's 
handwriting : ‘ Ammonites Sagittarius R. Hood’s Bay.’ 
AEgoceras (?) raricostatum Zieten, (p. 276). 
About this species Blake only states : ‘ The young forms are somewhat 
like the young of the next [AEgoceras obsoletum Simpson sp.], but differ 
by a slight appearance of a keel. I have not seen the A . exortus of Simpson,, 
but its description would lead to its identification with this. 
‘ Geological position. — Zone of A. oxynotus (top), Robin Hood’s Bay 
in hard nodules.’ 
One specimen in Blake’s collection [B.M. No. C. I9i95[, 72-2 mm. in 
diameter, is labelled in Blake’s handwriting : ‘A. raricostat R. Hood’s 
Bay.’ It is somewhat distorted, its whorls being unsymmetrically 
coiled, a form of distortion not infrequent in this species. The other 
specimens in the collection are from Peak. Of these, the largest [B.M. 
No. C. 19200], 63-2 mm. in diameter, and labelled in Blake’s handwriting r 
‘ Ammon, raricostatus Peak,’ is also unsymmetrically coiled. A smaller 
specimen [B.M. No. C. 19197], 53-5 mm. in diameter, in a rock fragment 
labelled in the same handwriting : ' Am. raricostatus Peak,’ is associated 
with two young specimens [B.M. Nos. C. 19198 and C. 19199], 16 and 
18-5 mm. in diameter respectively, each, especially the larger one, 
[No. C. 19199], exhibiting the slight appearance of a keel mentioned by 
Blake. Another example [B.M. No. C. 19196], 33 mm. in diameter is 
labelled in Blake’s handwriting : ‘A. raricost. Peak, Way Ft.’ It 
would seem then that in this case and in others relating to Middle and 
Lower Liassic forms, the expression ' Robin Hood’s Bay’ may include 
Peak at the southern end of the Bay. Or the specimens from Peak may 
have been obtained subsequent to the publication, or at any rate, the. 
writing of Prof. Blake’s observations. 
AEgoceras obsoletum Simpson sp. (p. 276, pi. VII., figs, ia, b). 
A specimen in the Blake collection [B.M. No. C. 17939] is obviously 
Naturalist 
