NOTES AND QUERIES. 
175 
Chjpeus Mullen, Wright. Great Oolite of Em slow-bridge, and of the railway 
cutting near Stonesfield. 
Tygimis Michelini, Cotteau. Corubrash, Islip ; but not common. 
Tijgurus pentagonalis, Phillips. Coralline Oolite, Bullingdon ; \7ery rare. — 
J. P. Whiteayes, F.G.S. 
Starfish in the Deep Ocean. — Sir, — In the article on " High and Low 
Life" by Mr. Roberts, the following passage occurs : "The enormous pressure 
of the opposite element (water), which in the homes of these starfishes must 
amount to at least a ton and a half on the square inch, is so greatly at variance 
with our belief, that we are confounded at the very outset of the inquiry." 
Why cannot the possibility of a starfish existing under such enormous pres- 
sure be accounted for on the same principle as the fact that our own species 
exists under a pressure sufficient to crush us to death ? Myself and a fellow 
student having discussed the point without arriving at any satisfactory conclu- 
sion, we shall feel greatly obliged if you will kindly enlighten us. — Yours, &c., 
G. H. and J. R. B. 
On Lower Lias Sub-Ditisions — A German sub-division of the Lower Lias 
is into zones named after their leading fossils. The beds lying consecutively 
under the Anmonites oxijnotus bed, are called by Oppel, one the " Obtusus 
Bed" (Ammonites obtusus), the other the "Tuberculatus Bed" (Pentacriuites 
tuberculatus ), The beds in England said to correspond with these have been 
recently, in accordance with the German method, named in the same way, except 
that the latter name is rejected in favour of an ammonite, A. Tunieri. 
The correlation stands thus : — 
Germany. Englatid. 
Zone of ■) ^^^^^^ Obtusus Bed Amm. Obtusus Bed=(A.) 
A. Oxynotiis. ) ^ ' 
A ^BucklLdi ] Tuberculatus Bed = Amm. Turneri Bed =(B). 
Now all this rigid zone-dividing looks well enough within doors, and I fervently 
hope it may be found equally to correspond with nature's pages, remembering 
that a bad mdcx to a book is worse than none at all. But that is not the sub- 
ject of my present inquiry. I wish now simply to question the correctness and 
advisedness of the above partition, so far as the Lower Lias in England is 
concerned. It must be admitted that if a bed be named after a leading fossil 
which prevails therein, the fossil selected for a key-ward to the bed should " be 
distinct and characteristic, else it is of feeble service for the pm*pose of nomen- 
clature and classification of strata. To come to particulai s : — If, in a bed 
( A -H B), the upper part of the bed ( A) contains any number of x's, and the lower 
part (B) any number of y's ; — then if .r=y, or if x differs from JJ by an almost 
inappreciable difference — it, of course, follows that for all practicable purposes 
A=B : that the bed (A + B) should not be split on such evidence, but be 
regarded as one zone. 
Such is the case with the above beds, the " Obtusus" and the "Tunieri." 
The above reasoning is applicable ; and before the sub-division of the bed 
marked A. B. be accepted, let the palaeontologists first settle the question of 
their guide-shells. It will be of service then to put the query does A. obtusus 
differ from A Turneri? Rather does not Amm. Turneri = A. obtusus = A. 
Smithii = A. stellaris ? 
If the latter is the case let us reject A. Turneri for a name yielding us a more 
distinct guidance : or call both divisions the " A. obtusus Zone J' 
