DUE TO DIFFERENT CAUSES 19 



Another large section of Drift deposits contains 

 rock debris and boulders, transported far from their 

 native place, and, as it were, across country. This 

 was formerly looked upon as evidence of the inrush 

 of the diluvial waters, but now it is well established 

 that these materials have been carried to their 

 present positions by the slow action of either land or 

 floating ice, and not by any sudden transport by 

 water. On the hills north of the Thames, fragments 

 from the Limestones and Coal Measures of Yorkshire 

 are not uncommon, while in the Eastern Counties 

 are found blocks and boulders ice-transported from 

 Scotland" and even Scandinavia. In this section 

 of the Drift marine shells are occasionally met with. 



Other portions of the superficial detritus may be 

 attributed to the breaking up of the surface of the 

 rocks by weathering and by the extreme cold of the 

 Glacial period. 



In this way the origin of the larger proportion of 

 the superficial deposits of loam, gravel, and sand has 

 been accounted for, and shown to be due to the same 

 agencies, though often acting with greater energy 

 and force, as those which now act upon the surface of 

 the land, and that, so far from being the result of a 

 sudden and transient catastrophe, they result from 

 the long-continued and gradual action of known 

 agencies, and represent the work of a long period of 

 time. 



I need not, however, dwell upon these recognised 

 Drift deposits, which will be found described in the 

 various text-books of Geology, and in papers published 



C 2 



