124 HATCHER— OLIGOCENE AND MIOCENE DEPOSITS. lAprilS, 



thermore it not only does not account for but is actually opposed 

 to the present distribution of the fossils. If, as we are told, the 

 fine clays were deposited over the deeper and quieter waters of the 

 lake and the sandstones and conglomerates about the mouths of 

 rivers and along the shores, why, I may ask, is it that the former 

 contain absolutely by thousands the remains of giant land-tortoises, 

 while these if not entirely absent are conspicuously rare in the 

 sandstones, while the few examples of Trionyx, an aquatic turtle, 

 have, in so far as I know, all been recovered from the sandstones ? 

 I have myself collected a number of these latter from the sand- 

 stones. If the land-tortoises were brought into the lake by the 

 rivers, ought we not to expect that their remains would be found in 

 at least as great an abundance in the sandstones as in the clays ? 

 Again, while it is quite possible to conceive of even a huge animal 

 of such elephantine size as was Titanotherium as having met death 

 by drowning or otherwise in or near some stream, where the dead 

 body inflated by gases would be carried out by the current into the 

 waters of the lake to sink later, allowing the bones to be preserved 

 in the clays at the bottom, it is difficult to understand how such 

 examples could be other than exceptional, and it is totally incapable 

 of explaining the present distribution and abundance of such bones. 

 In such a case as that just supposed it seems quite probable that 

 once decomposition had proceeded far enough to weaken the body 

 walls sufficiently to permit of the escape of the confined gases, the 

 carcass would sink to the bottom and the bones of the skeleton be 

 preserved in approximately their normal position relative to one 

 another, just as are the skeletons of marine reptiles in the chalk 

 beds of western Kansas or at Lyme Regis in England. If this 

 were the case we should expect to find complete skeletons at least 

 fairly common, but they are in fact exceptionally rare, and for 

 every even approximately complete skeleton to be found there are 

 scores of isolated skulls and other bones. Taking Titanotherium as 

 an example, I have myself collected nearly two hundred skulls of 

 this animal, while the number of fairly complete skeletons at pres- 

 ent known may be counted on the fingers of one hand. What 

 is true of this animal applies likewise to the others found in 

 the beds. 



But, it will be asked, if the lake theory is so objectionable, why 

 do you not offer a better ? Such has already been done by 

 Matthew, and it is the purpose of the present paper to support 



