PREHISTORIC TIMES. m 



al being, representing man, then flourished, some signs of his existence 

 could hardly have escaped unnoticed, in the shape of implements of 

 stone or metal, more frequent and more durable than the osseous re- 

 mains of any of the mammalia." 



It is true that few of our existing species, or even genera, have as 

 yet been found in miocene strata ; but if man constitutes a separate 

 family of mammalia, as he does in the opinion of the highest authori- 

 ties, then, according to all paleontological analogies, he must have had 

 representatives in miocene times. We need not, however, expect to 

 find the proofs in Europe ; our nearest relatives in the animal kingdom 

 are confined to hot, almost to tropical climates, and it is in such coun- 

 tries that we are most likely to find the earliest traces of the human 

 race. 



M. Morlot has made some interesting calculations respecting the 

 age of geological formations in SAvitzerland. The torrent of the 

 Tiniere, at the point where it falls into the Lake of Geneva, near Ville- 

 neuve, has gradually built up a cone of gravel and alluvium. In the 

 formation of the railway this cone has been bisected for a length of 

 1,000 feet, and to a depth, in the central part, of about 32 feet 6 

 inches above the level of the railway. The section of the cone thus ob- 

 tained shows a very regular structure, which proves that its formation 

 was gradual. It is composed of the same materials (sand, gravel, and 

 large blocks) as those which are even now brought down by the stream. 

 The amount of detritus does, indeed, differ considerably from year to 

 year, but in the long-run the differences compensate for one another, 

 so that, when considering long periods, and the structure of the whole 

 mass, the influences of the temporary variations, which arise from me- 

 teorological causes, altogether disappear, and need not, therefore, be 

 taken into account. M. Morlot's estimates assign about 6,000 years 

 for the formation of the lower layer of vegetable soil, and 10,000 

 years for that of the whole existing cone. But above this cone is 

 another, which was formed when the lake stood at a higher level 

 than at present, and which M. Morlot refers to the period of the 

 river-drift gravels. This drift-age cone is about twelve times as large 

 as that now forming, and would appear, therefore, on the same data, 

 to indicate an antiquity of more than 100,000 years. 



Again, it will be remembered that, side by side with the remains 

 of Arctic animals, have been found others indicating a warm climate, 

 such for instance as the hippopotamus. This fact, which has always 

 hitherto been felt as a difficulty, is at once explained by the suggestion 

 of a change every 10,000 or 11,000 years, from a high to a low tem- 

 perature, and vice versa. But a period of 10,000 years, long as it may 

 appear to us, is very little from a geological point of view. We can 

 thus understand how the remains of the hippopotamus and the bones 

 of the musk-ox come to be found together in England and in France. 

 The very same geological conditions which fitted our valleys for the 



