ANIMALS LIVING IN DEEP SEAS. 



155 



bed of blue lias filled with the Gryphcea arcunta, in the mountains 

 on the lake of Annecy, and fragments of oolite, like that of Glou- 

 cestershire, from the top of Mont Grenier, near Chamberry, left me 

 no doubt of the identity of the formations of England, France and 

 Savoy ; and no reason can be assigned, which might lead us to infer, 

 that the similar formations in each country were not cotemporaneous. 

 With respect to very remote countries, or the countries in opposite 

 hemispheres, we have, as yet, few data to determine whether there 

 be a similarity of fossil remains, which can identify formations that 

 may appear analogous, or even whether such a similarity could iden- 

 tify them, when they occur in very different latitudes and under very 

 different degrees of temperature. 



There is another circumstance, independent of climate or remote 

 distance, that may have occasioned a change in the genera, and even 

 in the orders and classes of animals, whose remains are found in sim- 

 ilar strata. The ocean may have been much deeper in one part, 

 than in another not very remote, and the deepest bed of the ocean 

 might support genera of pelagian animals;^ while a more shallow 

 adjacent part might be tenanted by different genera, and even diffe- 

 rent orders and classes of animals, whose organization fitted them 

 for moving near the surface of the water. The transition strata were 

 probably formed under a great depth of the sea : and few of the ani- 

 mals, whose remains are found in these strata, possessed in an emi- 

 nent degree the power of locomotion. The animals possessing this 

 power, were, chiefly, chambered univalve Mollusca; their shells are 

 divided, and have a tube or siphunculus passing through each cell, 

 by which they were enabled to exhaust the water, and rise to the 

 surface from immense depths. The shells of these animals did not 

 form an outer covering, but were partly enveloped in their bodies, 

 and appear to have performed the function of an air bladder. They 

 had heads surrounded by feelers and large eyes ; their beaks were 

 like those of the parrot. f The feelers which surrounded their heads 

 served them for seizing their prey, and for swimming and walking at 

 the bottom of the sea ; they swam whh their heads behind them ; 

 and when they walked, their heads were downward. There are 

 only two known genera of chambered animals of this class inhabit- 

 ing the present seas; the Nautilus, and the Spirula, — their shells are 

 spiral : the greatest number of chambered fossil shells found in the 

 upper secondary strata are also spiral, and are well known as Ammo- 



* Pelagian animals, so called by naturalists, because they live in deep seas. 



t The animals of this Order, to which Cuvier has given the name of Cephalo- 

 podes, from their feelers, which serve as feet, being attached to their heads, com- 

 prise several genera, as the cuttle-fish, the calamar, &c. but the latter animals hare 

 no shells. The Argonauta, common in the Mediterranean, has an open uncham- 

 bered shell. There are numerous minute microscopic chambered shells found in 

 the present seas, but according to Cuvier the living animal has never yet been ob- 

 served. — Rtgne Animal^ tome ii. p. 367. 



