CHAT>. xi. AGE OF NATCHEZ FOSSIL MAN. 205 



at more than one level, and the ancient mounds of the Ohio, 

 with their works of art, described at p. 39, are newer than 

 the old terraces of the mastodon period, just as the (rallo- 

 Koman tombs of St. Acheul or the Celtic weapons of the 

 Abbeville peat are more modern than the tools of the mam 

 moth-bearing alluvium. 



In the first place, I may remind the reader that the vertical 

 movement of two hundred and fifty feet, required to elevate 

 the loess of Natchez to its present height, is exceeded by the 

 upheaval which the marine stratum of Cagliari, containing 

 pottery, has been ascertained by Count de la Marmora to have 

 experienced, p. 177. Such changes of level, therefore, have 

 actually occurred in Europe in the human epoch, and may 

 therefore have happened in America. In the second place, I 

 may observe that, if, since the Natchez mastodon was embedded 

 in clay, the delta of the Mississippi has been formed, so, since 

 the mammoth and rhinoceros of Abbeville and Amiens were 

 enveloped in fluviatile mud and gravel, together with flint 

 tools, a great thickness of peat has accumulated in the Valley 

 of the Somme ; and antecedently to the first growth of peat, 

 there had been time for the extinction of a great many mam 

 malia, requiring, perhaps, as shown at p. 144, a lapse of 

 ages many times greater than that demanded for the for 

 mation of thirty feet of peat, for since the earliest growth of 

 the latter there has been no change in the species of mammalia 

 in Europe. 



Should future researches, therefore, confirm the opinion 

 that the Natchez man coexisted with the mastodon, it would 

 not enhance the value of the geological evidence in favour of 

 man's antiquity, but merely render the delta of the Mississippi 

 available as a chronometer, by which the lapse of post-pliocene 

 time could be measured somewhat less vaguely than by any 

 means of measuring which have as yet been discovered or 

 rendered available in Europe. 



