ON GEOLOGIC HISTORY. 281 



ways resembles that of Prometheus of old, who presented to 

 Jupiter what, though it seemed to be an ox without blemish, 

 was merely an ox-skin stuffed full of bones and garbage. 



There is another very remarkable class of facts in geolo- 

 gical history, which appear to fall as legitimately within the 

 scope of argument founded on final causes, as those which 

 bear on the appearance of man at his proper era. The period 

 of the mammiferous quadrupeds seems, like the succeeding 

 human period, to have been determined, as I have said, by 

 the earth's fitness at the time as a place of habitation for 

 creatures so formed. And the bulk to which, in tlie more 

 extreme cases, they attained, appears to have been regulated, 

 as in the higher mammals now, with reference to the force 

 of gravity at the earth's surface. The Megatherium and the 

 Mastodon, the Dinotherium and the extinct elephant, in- 

 creased in bulk, in obedience to the laws of the specific con- 

 stitution imparted to them at their creation ; and these laws 

 bore reference, in turn, to another law, — that law of gravity 

 which determines that no creature which moves in air and 

 treads the surface of the earth should exceed a certain weight 

 or size. To very near the limits assigned by this law some 

 of the ancient quadrupeds arose. It is even doubtful whether 

 the Dinotherium, the most gigantic of mammals, may not 

 have been, like the existing sea-lions and morses, mainly an 

 aquatic quadruped ;* — an inference grounded on the circum- 

 stance that, in at least portions of its framework, it seems to 

 have risen beyond these limits. Now, it does not seem won- 

 derful that, with apparent reference to the point at which 



* The great Dinotherium (dreadful beast), a beast furnished with large 

 tusks turned downwards like those of the walrus, but fixed to the lower 

 jaws, possibly belonged to the Sirenia (mermaid animals). This animal 

 inhabited the embouchures of great rivers, and used the enormous tusks 

 of the lower jaw for uprooting aquatic plants, on which it fed.— " Old 

 Bones," by the Rev. W. S. Symmonds. Published in March 1861.— 

 L. M. 



