C— GEOLOGY 8s 



some other parts by Deeley, Wilson, Beeby Thompson, Jerome Harrison 

 and Shotton. 



The ' Older Drifts,' as already pointed out, are essentially either 

 north-western (or Welsh) or north-eastern in composition. We may now 

 examine them to determine whether they record more than one glacial 

 epoch. For this purpose we can divide the region into two parts along a 

 line running roughly from Derby — Lichfield — Tamworth — Coventry — 

 Stratford-on-Avon to Moreton-in-the-Marsh. 



East of this line two distinct sets of glacial deposits can be recognised on 

 lithological and stratigraphical grounds . The older of the two , as developed 

 in the north, is of Pennine origin, and was carried by ice travelling from the 

 north-west (Figs. 4, 5, and 3) ; but near Coventry and Rugby drift occupying 

 an analogous position contains chalk and flints, and can be described 

 as a sort of chalky boulder clay. Its apparent southerly limit is shown in 

 Figs. 4, 7 and 2, 6- In the intermediate district little is known, but near 

 Hinckley and perhaps also at Bedworth part of the older series consists 

 of well-bedded, probably lacustrine deposits. The drifts on the Blythe- 

 Avon watershed near Stratford-on-Avon, and the ' Campden Tunnel 

 Drift ' near Moreton appear to be Welsh in origin. ^ They have both been 

 regarded as probably older than the Great Eastern glacier (Tomlinson). 



Throughout all this eastern region the upper or more recent drift has 

 been derived from the north-east and often consists of a true chalky 

 boulder clay. It has generally and, I think, correctly been referred to the 

 Great Eastern glaciation of Harmer. 



If we examine the map (Fig. 3) showing the distribution of glacial 

 striae and of boulders of Midland origin in this eastern region, we note 

 that the Pennine group travelled towards the south-east, whereas there is a 

 great stream of Leicestershire rocks towards the south and south-west. 

 These two directions are certainly an index of the movements of the older 

 and more recent glaciers respectively. 



Between the lower and the upper boulder clays in the Hinckley-Cov- 

 entry-Rugby district there is a persistent bed of gravel and sand. Some- 

 what similar deposits, the Jurassic gravels of Miss Tomlinson, underlie 

 the ' Main Eastern ' boulder clay of the Stratford area. The ' Ditchford ' 

 or ' Paxton ' gravels of the Moreton district occupy an analogous position 

 with respect to the chalky ' Moreton Drift ' (Tomlinson and Dines). 

 See Fig. 4, g- In the Jurassic gravels near Stratford, a single tooth of 

 an archaic form of Elephas antiquus has been found, which is suggestive 

 of interglacial conditions. Near Coventry both cold and warm climate 

 fossils have been recorded by Shotton. In view of the close association 

 of these deposits with two glacial series, the presence in them of tundra 

 and temperate fossils is not so contradictory as would at first sight appear, 

 especially as we must allow that vast lengths of time may be represented 

 by comparatively thin deposits in a watershed-area, like this, where the 

 levels of the valley floors were not much altered either by erosion or 

 deposition. 



* See, however, note on p. 82. 



