NOTES AND QUERIES. 



175 



Clypeus Mulleri, Wright. Great Oolite of Emslow-bridge, and of the railway 

 cutting near Stonesfield. 



Py gurus Michelhii, Cotteau. Cornbrash, Islip ; but not common. 



Pi/gurus pentagonalis, Phillips. Coralline Oolite, Bullingdon; very rare. — 

 J. E. Whiteaves, E.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 enonnous 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. U. B. 



On Lower Lias Site-Divisions — A German sub-division of the Lower Lias 

 is into zones named after then leadiug fossils. The beds lying consecutively 

 under the Ammonites oxynotus bed, are called by Oppel, one the " Obtusus 

 Bed" (Ammonites obtusus), the other the " Tuberculatus Bed" (Pentacrinites 

 tuberculatus J, 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. Turner i. 



The correlation stands thus : — 



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 index 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 purpose of nomen- 

 clature and classification of strata. To come to particulars : — If, in a bed 

 (A + 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 x=y, or if x differs from y 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 "Turneri." 

 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 ? Bather 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" 



Germany. 



England. 

 Amm. Obtusus Bed=(A.) 



Amm. Turneri Bed =(B). 



