406 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 6, 



forming off the neighbouring coast, aiul are covered in some spots 

 by dark-coloured clay containing the remains of quadrupeds of 

 extinct species, the Megatherium, Mylodon, Mastodon giganteus, 

 Elephas priniigenius, the Horse and others, with a large Chelonian*. 

 I visited numerous localities on the Brunswick canal, near Darien, 

 in company with Mr. Hamilton Couper, to whom we owe the dis- 

 covery and careful exhumation of these remains, nearly all of which 

 he has munificently presented to several public museums in the 

 United States, especially those of Washington and Philadelphia. 

 Everywhere I observed that there is no intermixture of the deposit 

 containing the land animals with the subjacent bed containing the 

 marine shells, and the mammalian remains appear to me to have 

 been deposited in one of the arms of the ancient delta of the Alata- 

 maha, when the relative level of land and sea was not the same, and 

 yet differed but slightly from the present. 



Mr. Couper's collection of the fossil shells underlying the bones 

 comprises a large proportion of all the species which have been 

 found on the coast of South Carolina, Georgia and Alabama. I 

 have myself seen most of these fossils in situ, near Savannah or in 

 the excavations made for the Brunswick canal, and they establish 

 the fact that the ocean was inhabited before the time of the extinct 

 mammalia by precisely the same conchological fauna as now : nor 

 ought this conclusion to surprise us, as it is quite in harmony with 

 that which I formerly deduced from the association in all parts of 

 North America, from Canada to South Carolina, of the bones of the 

 Mastodon and other lost quadrupeds with freshwater and land shells, 

 not differing specifically from those of the adjoining rivers, lakes 

 and forests. Such facts seem distinctly to imply that tlie temperature 

 both of the atmosphere and the ocean has not materiaily changed 

 since the time of the lost quadrupeds. 



Secondly, on the coast of Georgia I examined, with Mr. H. Cou- 

 per, the position of those submerged trunks or stools of the cypress 

 ( Cupressus disticha) which Bartram formerly alluded to in his 'Tra- 

 vels,' as showing that the level of the land on this coast had changed 

 relatively to the sea in modern times. These trees can only grow 

 in freshwater swamps, and there they are not permanently sub- 

 merged at their base even in fresh water. At the mouth of the 

 Alataraaha they are now found below the level of high tide in the 

 salt marshes, with a deposit of mud over them. They also occur all 

 with their upper surfaces cut off at the same level, and covered with 

 several feet of alluvial matter in swamps higher up than the line of 



* The Hippopotamus and Sus were formerly enumerated by Mr. Cooper and 

 Dr. Harlan in their list of the fossil genera met with in digging the Brunswick 

 canal. But Prof. Owen, in a communication recently sent to the Academy of 

 Sciences at Philadelphia, has shown that the tusk referred to the Hippopotamus 

 belongs to the Mastodon, so that there is now no evidence of a fossil Hippopota- 

 mus in America. The jaw to which the name of Sus americana had been applied 

 exhi1)iis a new type of organization, making some approach both to Lophiodon 

 Jind Toxodon, but differing from cither. For this fossil Mr. Owen has proposed 

 the name of Ilarlanus ameiicanus. 



