ANCIENT GLACIERS IN EASTERN HEMISPHERE. 161 



500 feet. But where is it? Certainly not in Western 

 Europe, for the chalk does not attain so great an elevation 

 except in a few isolated spots.' * 



" It has been further pointed out by Mr. Skertchly, that 

 the condition of the flints in this deposit furnishes strong 

 evidence that they could not have been carried by floating 

 ice nor upon a glacier, for, in either of the latter events, 

 there must have been some exposure to the weather, which, 

 as he remarks, would have rendered them worthless to the 

 makers of gun-flints, whereas they are now regularly col- 

 lected for their use. 



" The way in which the boulder-clay is related to the 

 rocks upon which it rests is a conclusive condemnation of 

 any theory of floating ice ; for example, where it rests up- 

 on Oxford Clay, it contains the fossils characteristic of 

 that formation, as it is largely made up of the clay itself. 

 The exceptions to this rule are as suggestive as those cases 

 which conform to it. Each outcrop yields material to the 

 boulder-clay to the south westward, showing a pull-over 

 from the northeast. 



" One of the most remarkable features of the drift of 

 this part of England is the inclusion of gigantic masses of 

 rock transported for a short distance from their native 

 outcrop, very often with so small a disturbance that they 

 have been mapped as in situ. Examples of chalk-masses 

 800 feet in length, and of considerable breadth and thick- 

 ness, have been observed in the cliffs near Cromer, in Nor- 

 folk, but they are by no means restricted to situations 

 near the coast. One example is mentioned in which 

 quarrying operations had been carried on for some years 

 before any suspicion was aroused that it was merely an 

 erratic. The huge boulders were probably dislodged from 

 the parent rock by the thrust of a great glacier, which first 

 crumbled the beds, then sheared off a prominent fold and 



* Geikie's Great Ice Age, p. 360. 



