438 



THE GEOLOaiST. 



tlirougTi wliicli the major part of the Thames flows, are of marine species, 

 and most of them extinct. In the superficial gravel have been found 

 fiuviatile shells, most of them of recent species, with the remains of ele- 

 phant, rhinoceros, hippopotamus, and other large terrestrial quadrupeds." 



As regards earthquakes, as a geological dynamic, Hunter states — 



" I formerly observed that earthquakes very probably raised islands ; 

 that on the surface of such there would be found shells, and in vast quan- 

 tity, recent, dead, and fossilized. . . . This upraising of the bottom of the 

 sea above the surface of the water, will also raise up along with it all the 

 shell-fish that lay on the surface of the bottom, as also dead shells, and in 

 the substance of the earth all the deeper-seated substances imbedded or 

 enclosed in stone, ciialk, clay, etc., which I have said constitutes the true 

 fossil. This appears to be the state of the case on and in the Island 

 of Ascension ; the whole surface of this island is covered with shells, and 

 some so perfect as to have their ligaments still adhering. There is, besides, 

 a vast quantity of lava, and other volcanic matter, all of M"hich shows it 

 most probably arose in this way ; because such recent alteration in the sea, 

 so as to have exposed so much of its bottom, and so recently as to have the 

 animal part of the shell still adhering, and the very name implies its rise. 

 I suspect that many of those shells found on land near the surface, on the 

 tops of mountains, have been exposed in this way." — P. xlvii. 



Owen remarks on the ridiculous derivation of the name of the island : — 



" This is very ingenious ; but the superstitious Spaniard had little 

 thought of the geological causes of tlie island, when he discovered it on 

 the evening of ' Ascension Day.' " 



Poor Joao de Nova Galego little expected that he should be thus mis- 

 quoted in the eighteenth century. 



With respect to the conditions under which mammalian remains are 

 imbedded in comparatively recent geological deposits, Hunter wrote — 



" In peat, one could conceive that the trees had only to fall, and after- 

 v. ards to sink down into it ; but I believe no such wood grows in peat, 

 therefore they must have been brought there, and that only by water ; or 

 [they may have] grown there prior to the formation of peat. But the 

 animals which could come there had only to die on the surface, and in time 

 they would also sink deeper and deeper into it ; and this I imagine might 

 be the case with the beavers in this country, whose bones are found in the 

 peat-mosses in Berkshire. Or, as peat is supposed to grow, we can con- 

 ceive it rising higher and higher above such substance. 



" Bones are also found in gravel, clay, marl, loam, etc. ; and as we have 

 found the sea-horse bones \_ILippoj[)otamus'\ in gravel, etc. in this country, 

 I am inclined to think that such situations have been shores or arms of the 

 sea, at last constituting mouths of rivers, v\here the animals have been 

 accidentally swept away by floods, accidentally drowned, etc., where gravel, 

 clay, etc. have subsided, as before described ; for it gives more the idea of 

 being a consequence of the seti leaving the land than an effect produced by 

 a continuance of the sea in the part, according to our idea of the formation 

 of the true fossil. But the difficulty is to apply this to the bones of some 

 aninuils that do not now exist in the same countries where they are found ; 

 as also [to] the bones of animals that probably do not now exist in any 

 country. 



" This looks like a destruction of the whole species of such animals at 

 the time [during] which [those] animals were probably confined to such 

 countries; and which might also be the case with the beaver in this 

 country ; and it beir.g a more universal animal, its species is ]n-eserved in 

 other parts. The same observations apply to the sea-horse \ILippopota- 

 mus\ as also to the elephant." .... 



