hunter's posthumous paper on fossils. 325 



may even have a disposition to form itself into nodules ; and probably 

 some circumstance may lead to it, as having an extraneous body in it, 

 as part of a vegetable, round which it seems to accrete, assisted in this 

 operation by what may be in solution in the water, also forming what 

 is called the Ludus Helmontia." — P. xxi. 



" From this account it would appear that there is a kind of system 

 going on ; that the sea is the great reservoir of the materials of this 

 globe, and the rivers, tides, currents, &c. of the sea, the active parts, 

 without which the world would be at rest. When we consider the 

 consequence of all these operations, we may be better able to form an 

 opinion of the mode of new increase of matter in some places on the 

 surface of this globe, in which will be vegetable and animal produc- 

 tions, which will give some idea of fossilization." — P. xvii. 



Besides the indications of the general principles which Hunter had 

 discovered for himself, or had accepted for his guidance, in the study and 

 contemplation of the grand phenomena of the past creations and revolu- 

 tions of the earth's surface, we find in the remarkable essay recovered from 

 his posthumous manuscripts some instances of the results of the special 

 application of those principles to particular geological phenomena. 



Take those which must have most frequently presented themselves 

 to his observation, as, e. g., in the valley of the Thames, and note the 

 broad interpretation that he gives of the facts so observed. " Probably," 

 he writes, " the whole flat tract of the river Thames, between its lateral 

 hills, was an arm of the sea ; and as the German Ocean became 

 shallower, it was gradually reduced to a river : and the composition of 

 this tract of land, for an immense depth, would show it, viz. a gravel, 

 a sand, and a clay, with fossil shells in the clay 200 or 300 feet deep, 

 all deposited when it was an arm of the sea, and above which are 

 found the bones of land-animals, where it has been shallow." — P. xv. 



Hunter does not, indeed, specify the nature of the shells : they are, 

 however, of a kind that coidd leave no doubt on his mind of their 

 marine character. "With his fossil specimen of Strombus coronatus, 

 Dfr. (No. 561), he has placed the recent Strombus accipitrinus from the 

 South American seas. He had also obtained Bostellaria macroptera, Lam. 

 (No. 570), from the eocene tertiary at Hordwell, Hants ; Voluta nodosa, 

 Sby. (No. 747), from the London clay ; Mitra elongata, Lam. (No. 781), 

 from the eocene at Grignon, near Paris ; the gigantic Cerithium (No. 

 783), from the same formation and locality ; the Crassatella tumida, 

 Dh. (No. 1095), from Nummulitie strata of the Swiss Alps ; and the 

 great Nautilus miperialis from Sheppey (No. 137), so like the pearly 

 Nautilus from the nldia seas : — all these shells, selected from a hundred 

 other specimens in Hunter's cabinet, must have presented to their col- 



