6/6 EVOLUTION OF THE HORSE. 



man had learned to manufacture that alloy from copper 

 and tin, and began to make weapons with it, but he knew 

 nothing of the working of iron, until the approach of his- 

 toric times, the length of which is now about 7,000 years. 

 The " Drift " (loose deposits of clay, gravel and sand) 

 of the Great Ice Age was formerly regarded as a result 

 of Noah's Flood, and consequently the Glacial Period 

 was called the Diluvial Period, which term is frequently 

 (though wrongly) used by Continential geologists. 



The following is a summary of the foregoing periods : — 



The above classification is merely one of convenience, 

 because no sharp line of demarcation can be drawn between 

 any of these periods, except the Archaean, the fused rocks 

 of which form the floor of the graves of the ancestors and 

 other relatives of all living things. Speaking of the Recent 

 Period, Professor Lapworth, F.R.S., says : " These so- 

 called ages in all hkehhood shaded insensibly into the 

 other. In some districts, stone implements were employed 

 probably long after they had fallen into disuse elsewhere. 

 In the later stone ages, unpolished tools were probably 



