REVIEWS OF NEW PUBLICATIONS. 445 



They abound in fossil remains, 'which ascend from the ancient zoophytes and 

 plants in the lower strata to the gigantic and long-since extinct reptiles in the 

 upper, viz. the chalk. — The tertiary rocks — which, like the preceding, consist of 

 subaqueous deposits from the detritus of ancient formations — lie in the basins 

 of the chalk-beds. " They abound in shells, plants, zoophytes, Crustacea, &c. ; 

 and in them, with but one exception, the bones of Mammalia first appear." — 

 Lastly, the supra-tertiary strata form the surface of the country, consisting of 

 alluvial or water-worn matter* Here again we find the fossil remains of extinct 

 animals, but likewise, in addition, those of existing species. 



In a former article we adverted to the theory, that the world was originally 

 filled with gas — -an hypothesis supported by " Sir John Herschel, Bart.,'* and other 

 astronomers. Thus some of the heavenly bodies are mere clouds of attenuated light, 

 While others are curdling into separate masses, and others again present an 

 appearance more nearly resembling the structure of our own globe ; and every 

 variety exists between the states to which we have alluded. 



It has been argued, from the presence of tropical vegetation in British rocks, 

 that our country must once have possessed a tropical climate ; and although the 

 existence of streams whose regular office it is to convey the products of tropical 

 climes to temperate regions, may well serve as a caution against rash and hasty 

 conclusions, we think the existence of tropical vegetation in this island in all 

 probability not thus drifted, seems strongly in favour of the theory — now tolerably 

 certain — that districts in our day temperate have in past cycles experienced the 

 ardour of a tropical sun. 



At p. 66, Dr. Mantell describes the singular and highly interesting discovery 

 — first announced in the American, Journal of Science, in 1822 — of two perfect 

 impressions of human feet in Sandstone, observed in a quarry at St. Louis, on the 

 western bank of the Mississippi. They were at first supposed to have been 

 carved in the stone by the Indians ; but the anatomical accuracy of the im- 

 pressions, which, it is said, would have done honour to the chisel of a Chantbey, 

 is strongly opposed to this conclusion. They are of average size, and in the 

 position of the feet of a man standing " at ease." " No doubt exists in my 

 mind," observes our author, " that these are the actual prints of human feet in 

 soft sand, which was quickly converted into solid rock by the infiltration of cal- 

 careous matter." Without the slightest desire of invalidating this argument, we 

 may mention the difficulty involved in these being the only two impressions. If 

 they were actually unique, and unless the man who has thus unwittingly excited 

 the interest of posterity, possessed wings, how did it happen that no other prints 

 were discovered ? Dr. Mantell, however, promises us further enlightenment ori 

 the point at a future opportunity. 



Those interesting phenomena the geysers of Iceland are alluded to in a subse- 



VOL. III.- NO. XXIII. 3 N 



