XXVni rROCKEDINGS, 



There is evidence near Caddington of the great northern ice- 

 sheet with glaciers at its southern margin, in beds of boulder-clay, 

 the clay itself being the ground-up surface-material of the district 

 where it is now found, and often having much chalk in it, also 

 of local derivation, whence it is called the " chalky boulder-clay." 

 The stones or boulders which it contains, mostly water- worn and 

 frequently ice-scratched, have been brought down by glaciers from 

 higher land in the north, west, and east, often from great distances. 

 In this boulder-clay no relics of man are found, though human 

 relics occur immediately above it ; but bones of the great hairy 

 elephant or mammoth, of the reindeer, and of other animals con- 

 temporaneous with man, occur in a stratum of sand, gravel, and 

 clay intercalated in it. After its deposition the land probably sank 

 beneath the surface of the icy sea, and was then re-elevated to a 

 greater height than it now stands. The rivers then were broad 

 and ran at great heights, as is known ' ' by the deposits of river- 

 gravel, sand, brick-earth, and fresh-water shells which occur in 

 terraces on the hill-sides bordering the Thames Valley. In these 

 deposits of gravel, sand, and brick-earth, relics of the primeval 

 human savage first appear. In some positions these relics are 

 comparatively abundant, not on the surface, but imbedded amongst 

 the constituent stones of the gravel and sand, or fixed in the brick- 

 earth a hundred or more feet above the present river-level." 

 ('Man, the Primeval Savage,' p. 7.) 



Caddington is on the Chalk capped with re-distributed Tertiary 

 beds, brick-earth, and gravel. The brick-yards near the village 

 are from 550 to 6U0 feet above sea-level, and the water-level in 

 the Chalk — the level of permanent saturation — varies from about 

 110 to 160 feet beneath the surface of the ground. This probably 

 represents the extent of the depression in the water-level since Man 

 first took up his residence on the shores of the ancient lake or 

 swamp whose bed has been traced by Mr. Smith in pits on both 

 the Hertfordshire and the Bedfordshire side of Caddington. Every 

 important find, however, has been made in pits in our own county, 

 and it was these which were now visited. 



The pits are in Drift (brick-earth, etc.) and Tertiaiy remanie 

 beds, and arc worked for gravel as well as for clay and sand for 

 brick-making. After examining the section in one of the pits, 

 Mr. Cameron stated that the Tertiary beds, upon which lies the 

 PaloDolithic floor with its artificially-raised heaps of flints, were 

 Reading sands and clays probably estuarine in origin, and that the 

 bed immediately above was brick-earth. The section was very 

 obscure, the sides of the pit having fallen in, but Mr. Smith stated 

 that above the brick-eartli he had found contorted beds of clay 

 and gravel with Palaeolithic implements and flakes, then remanie 

 boulder-clay with sub-angular gravel above, again with Paleolithic 

 implements and flakes, the whole being capped by reddish-brown, 

 tenacious drift clay, and surface-soil with Neolithic implements of 

 black lustrous flint, etc. 



There are thus three distinct lavers in which Palaeolithic flint 



