THE PLEISTOCENE SEKIBS 



625 



coaM-liur which i> in many places a line of buried dirt's. Such 

 rlill's an- intri -tried 1 > y tlir present coast -line at SewerKy in 

 Yorkshire, and though they are not seen in Lincolnshire their 

 existence is proved by the depth of Qlacial deposits found at many 

 places on the east of tin- clialk-surfa< -. These deposits also enter 

 tin- valleys of the Wolds, and appear to have mantled the slopes 

 of the hills up to a height of at least 380 feet. 



The succession of beds seen in the cliffs near Bridlington and 

 Sewerby is as follows, and is from 60 to 1 00 feet thick : 5 



5. The Sewerby gravels. 



4. The Hessle Boulder-clay, 



3. The Purple Boulder-clay. 



2. The Basement Boulder-clay. 



1. Chalky gravel and Buried-clirT Beds. 



The buried -cliff beds are only seen at Sewerby, where they 

 are banked against the ancient coast -line above mentioned (see Fig. 





Fig. 206. CLIFF-SECTION AT SEWERBY (after G. W. Lamplugh). 



8. Sewerby gravel. 

 7. Purple boulder-clay. 

 6. Basement boulder-clay. 

 5. Chalky gravel. 



4. Blown sand ' 

 3. Rainwash 

 2. Pebble beach . 

 1. Chalk 



I Buried cliff 

 beds. 



206). From the old beach and the overlying raimvash bones and 

 teeth of the following Mammals were obtained : Elephas antiquus, 

 Rhinoceros meroni, Hippopotamus amphibius and Hycena crocuta. 

 Elsewhere the chalky gravel appears to form a nearly continuous 

 basal bed. The Basement Clay is of a greenish-grey colour, is 

 sometimes 30 feet thick, and includes twisted layers or patches of 

 sand which contain marine shells ; no fewer than 110 species have 

 been found, and among them are some which no longer Jive in 

 British waters, such as Nuculce Cobboldia, Tellina obliqua, Astarte 

 borealis, Fusus spitzbergensis, and F. Sam. 



The Purple and the Hessle boulder - clays have the same 

 characters as in Lincolnshire (see below). The commonest stones 

 in these and the lower clay have been derived from the Carboniferous 

 rocks to the north ward, but some have come from the Cheviot Hills, 



2s 



