356 THE POPULAR SCIENCE MONTHLY. 



pheric influences, and have been subjected to chemical changes and 

 the friction of sand and water. These causes produce the characteris- 

 tic " patina," which distinguishes genuine flint implements, and which 

 varies greatly according to the conditions under which the objects 

 have remained. It is of very different colors, but has never been suc- 

 cessfully imitated by artificial means. Many of the implements also, 

 like mine, are marked by a beautiful moss-like deposit of oxide of man- 

 ganese, called " dendrites," which is an additional guarantee of their 

 genuineness, as it is only produced by a long lapse of time. In the 

 gravel-pits in the neighborhood of Paris, on both banks of the Seine, 

 in many visits ranging over several years, I have been able to procure 

 a large number of worked flints, together with the usual fossil bones 

 that accompany them. So, too, in similar excavations at the Ponte 

 Molle, near Rome, at a long distance from the present bed of the Ti- 

 ber, and far above the limit of any possible inundation now, I have 

 obtained numerous specimens both of flints and bones. 



To go thoroughly over the arguments of the geologists, by which 

 the very great antiquity of such Quaternary deposits with their 

 contents has been established, would require more space than is at 

 my command. I will simply state a few facts, leaving others to 

 draw their own inferences from them. Implements of the St. Acheul 

 type have been found in place at the bottom of undisturbed gravel- 

 beds more than thirty feet deep, both at Abbeville and at Amiens, 

 and in the former locality peat-beds have been subsequently formed 

 in the more deeply excavated portion of the valley more than thirty 

 feet in thickness. Now, whatever may be the lapse of time need- 

 ful for the accumulation of such a mass of peat as this, it is all pos- 

 terior in date to the ancient implement-bearing gravels. At Amiens 

 Roman graves have been found in the superficial deposits at about 

 the present level of the river, and far below that of the Quaternary 

 gravels, showing that more than fifteen hundred years have pro- 

 duced scarcely any change in the configuration of the valley, so far as 

 its depth is concerned. So, too, on the top of Milford Hill, in the 

 neighborhood of Salisbury, England, are found Quaternary gravels 

 containing implements of the St. Acheul type. This hill is cut off 

 from the main spur to which it belongs by a transverse valley, which 

 proves that, at the time when the gravel was deposited there, such a 

 depression could not have existed, as in that case the water would 

 have flowed along the valley, and not left its contents on the top of 

 the hill. On each side of the hill is also a similar valley, which, for 

 the same reason, could not have been there when the gravel was de- 

 posited. Thus the top of the hill once formed the bottom of the bed 

 of a river flowing along a valley whose sides have now entirely dis- 

 appeared, and in their place a new valley has been excavated on each 

 side to the depth of one hundred feet. 

 . That these Quaternary gravels can not be owing to any sudden 



