26 TRACES OF THE GREAT ICE AGE IN DERBYSHIRE. 



further south between Alderwasley and Belper. A number of 

 patches of drift occur on the eastern flank of the Pennine Chain, 

 but it is not proposed to enumerate them here. In and near 

 Derby itself are several interesting sections of boulder-clay. 

 One near the top of Argyle Street, on Burton Road, overlies 

 Keuper clays. This contains many quartzites and coal-measure 

 pebbles, and Mr. R. M. Deeley found in it a fragment or frag- 

 ments of chalk, thus proving it to belong to the Great Chalky 

 Boulder-clay. Another interesting deposit occurs in the upper 

 part of Littleover Lane, where it is well exposed on either side 

 of the road. There are here numerous pebbles of coal-measure 

 ironstone, showing, on fracture, an interesting concentric structure 

 produced by weathering. In the clay-pit near the Firs Estate 

 Board School, the Keuper strata are brought into a nearly vertical 

 position by a fault, and the upper ends exhibit a recurving, which 

 has probably been produced by the passage of ice over the 

 surface. A sketch of this will be found in my paper, " On an 

 Exposure in the Keuper Clays and Marls, Derby," which appeared 

 in the /oi/rnci/ {Ja.nua.ry, 1891). 



Coming to the basin of the Trent, the glacial deposits have 

 been observed and correlated in an extremely careful manner by 

 my friend, Mr. R. M. Deeley, F.G.S. * He classifies them as 

 follows : — 



Neiver Pleistocene Epoch. 

 Later Pennine Boulder-clay. Interglacial River-gravel. 



Middle Pleistocene Epoch. 



Chalky Gravel. Great Chalky Boulder-clay. 



Melton Sand. 



Older Pleistocene Epoch. 



Middle Pennine Boulder-clay. Quartzose sand. 



Early Pennine Boulder-clay. 



The deposits of the Older Pleistocene Epoch consist of two 

 boulder-clays separated from each other by fiilse-bedded gravel, 



" Quarterly Journal, Geological Society, 1886," p. 438. 



