during the Formation of the Crust of the Earth, 181 



is very difficult to establish a clearly-marked line of demarcation 

 between the Tertiary epoch and the present. 



New Results. 



In 1848 and 1849, we had already indicated, in the ' Index 

 Palseontologicus ' (second part, pp. 746-913), several of the re- 

 sults contained in the present work with regard to the appear- 

 ance of organisms on the surface of the earth, but without 



a period of time answering at least to two generations of Cypresses. We 

 see therefore that each of the forests which gave origin to the formation of 

 one of the beds of this deposit lasted at least 11,400 years, before, being 

 buried in the soil, there was a fresh irruption of the waters and formation 

 of a new bog. The marshy soil of this new bog became solidified in its 

 turn, and enabled to produce a new forest of Cypresses, the duration of 

 which was not inferior to that of the former. Then this forest was buried 

 in its turn, and the same phsenomenon was repeated ten times in succes- 

 sion. For the last of these alternations, therefore, calculation gives the 

 following result : — 



Formation and solidification of the bog 1 ,500 .years. 



Duration of two generations of Cypress 11,400 „ 



Duration of the existing forest of Oaks after the drying 



and elevation of the soil 1,500 „ 



14,400 „ 



The first nine times there was no desiccation and elevation of the soil 

 after the development of the forests of Cypress, and the production of 

 intermediate oak-forests was not possible. But as the depressions of the 

 soil which terminated the existence of each forest of Cypress often pro- 

 duced a depression of the surface far below the level of the original bog, 

 we may without much chance of error retain this space of 1500 years for 

 each of the ten preceding periods, and we find then that the formation of 

 the entire deposit required a period of time equal to 11 X 14,400, that is to 

 say, 158,400 years; and during the whole of this immense period, the 

 vegetation of the country has for the most part retained the same charac- 

 ters ! At New Orleans, at 1 6 feet below the soil, in the fourth of these 

 beds from the surface, there has been found a well-preserved human skull, 

 corresponding perfectly in its form with the skulls of the actual aborigines 

 of America, and accompanied by the remains of burnt wood. From this 

 we must conclude that this country was inhabited 57,600 years (4 x 14,400) 

 ago by men of the American race. 



Such is Mr. Dowler's calculation. It is true that several elements of 

 this calculation are somewhat hypothetical ; but the facts suffice to show, 

 with very great probability, the immense duration of an epoch posterior to 

 the Diluvian period, at least if we do not choose to regard the strata below 

 the human skull as still belonging to the csenolithic age — an opinion which 

 does not appear to be supported by local observation in Louisiana. More- 

 over, it is worth while to remark that this Cypress {Taxodium distichum), 

 upon which it would appear that we may rest, in order to demonstrate the 

 long duration of the post-diluvian epoch, is one of the three species the 

 existence of which may be traced, according to M. Goppert, upon the soil 

 of Europe, from the upper Miocene to the actual epoch (under the name 

 of Taxodifes dubius). — E. Claparede. 



