

The Chalky and other Clays of Eastern England. 455 



so-called Glacial beds so largely composed of clay there. The 

 clayey matrix referred to was not only derivative, but it was derived 

 from beds close by, and, so far as we know, was home-grown, and 

 not imported from abroad. 



As to the other ingredients of the so-called Glacial clays ; these 

 consist of two entirely different sets of materials — namely, the 

 indigenous and home-grown on the one hand, and the foreigners 

 or erratics on the other. It has been calculated by more than 

 one observer that over 90 per cent, of the stones found in the 

 Chalky Clay are of home growth ; and it is probable that in all the 

 clays of Eastern England generally referred to the so-called Glacial 

 age, the proportion of home-grown boulders or stones is very largely 

 indeed in excess of the strangers and foreigners. 



The first and most important fact, therefore, to remember is that, 

 over a very large area in Eastern England, the contents of the 

 so-called Glacial clays, both the matrix and the stones in them, are 

 of local origin and not imported. Most of the writers on these 

 clays have been so impressed by the importance of these strangers 

 which form barely a tithe of the contents of the clays, that they have 

 neglected the more essential and more important lessons to be 

 derived from an examination of the local and home-grown ingredients 

 which they contain. I propose in this paper to entirely neglect the 

 foreigners, and to converge attention upon the natives, reserving the 

 discussion of the former for another occasion. 



These natives consist of two entirely different classes. One class 

 comprises more or less angular rubble, with its angles frequently 

 blunted, and with the rude facets on its polygonal blocks often 

 scratched ; the other consisting of pebbles rolled perfectly smooth, and 

 of various sizes, resembling sea- and river-shingle, these latter chiefly 

 composed of flints and of quartzites, flints predominating greatly. 



There can be no doubt whatever that these latter are the debris 

 of marine and fluviatile shingles. It has apparently been argued 

 by some that they were formed as pebbles during the so-called 

 Glacial period. I believe this to be a complete mistake, and, so 

 far as my own observations go — and I have worked pretty hard 

 among them — they all seem to me to be derivative, and to be the 

 debris of disintegrated Tertiary gravel and pebble beds. This view 

 has been growing of late years. 



Hutton, so far as I know, was the first to suggest that such gravels 

 may have been the debris of the disintegration of older shingle 

 beds. Thus he argues that these water- worn materials had their 

 great roundness from the attrition caused by the waves of the sea 

 upon some former coast, and that, after having been thus formed by 

 agitation on the shores, and transported into the deep, this gi'avel 

 contributed to the formation of Secondary strata, such as the 

 pudding-stone he elsewhere described ; and, lastly, that it was 

 " from the decay and revolution of these Secondary strata, in the 

 wasting operations of the surface, that have come those round 

 siliceous bodies which could not be thus worn by travelling in the 

 longest river." ("Theory of the Earth," vol. ii, p. 144, note.) 



