148 THE POPULAR SCIENCE MONTHLY, 



Thenay to be of niiocene date, or of Mr. Skertclily's from Brandon to 

 be glacial. The accepted point is, that the men who made the ordi- 

 nary flint implements of the drift lived in the Quaternary period char- 

 acterized by the presence of the mammoth in our part of Europe. 

 More than one geologist, however, has lately maintained that this Qua- 

 ternary period was not of extreme antiquity. The problem is, at 

 what distance from the present time the drift-gravels on the valley- 

 slopes can have been deposited by water-action up to one hundred feet 

 or so above the present flood-levels ? It does not seem the prevailing 

 view among geologists that rivers on the same small scale as those at 

 present occupying mere ditches in the wide valley-floors could have 

 left these deposits on the hillsides at a time when they had not yet 

 scooped out the valleys to within fifty or a hundred feet of their pres- 

 ent depth. Indeed, such means are insufiicient out of all proportion 

 to the results, as a mere look down from the hill-tops into such valleys 

 is enough to show. Geologists connect the deposit of the high drift- 

 gravels with the subsidence and elevation of the land, and the power- 

 ful action of ice and water at the close of the Glacial age ; and the 

 term " Pluvial period " is often used to characterize this time of heavy 

 rainfall and huge rivers. It was then that the rude stone implements 

 of palaeolithic man were imbedded in the drift-gravels with the remains 

 of the mammoth and fossil rhinoceros, and we have to ask what events 

 have taken place in these regions since ? The earth's surface has been 

 altered to bring the land and water to their present levels, the huge 

 animals became extinct, the country was inhabited by the tribes whose 

 relics belong to the neolithic or polished-stone age, and afterward the 

 metal-using Keltic nations possessed the land, their arrival being fixed 

 as previous to 400 b, c, the king of the Gauls then being called by the 

 Romans by the name Brennus, which is simply the Keltic word for 

 " king " — in modern Welsh brenin. To take in this succession of events 

 geologists and archaeologists generally hold that a long period is re- 

 quired. Yet there are some few who find room for them all in a com- 

 paratively short period. I will mention Principal Dawson, of Montreal, 

 well known as a geologist in this Association, and who has shown his 

 conviction of the soundness of his views by addressing them to the 

 general public in a little volume, entitled " The Story of the Earth and 

 Man." Having examined the gravels of St. Acheul, on the Somme, 

 where M. Boucher de Perthes found his celebrated drift implements, it 

 appeared to Dr. Dawson that, taking into account the probabilities of a 

 different level of the land, a wooded condition of the country, and great- 

 er rainfall, and a glacial filling up of the Somme Valley with clay and 

 stones subsequently cut out by running water, the gravels could scarce- 

 ly be older than the Abbeville peat, and the age of this peat he esti- 

 mates as perhaps less than four thousand years. Within this period Dr. 

 Dawson includes a comparatively rapid subsidence of the land, with a 

 partial reelevation, which left large areas of the lower grounds beneath 



