138 MAN AND THE GLACIAL PERIOD. 



tending from the Bristol Channel to the mouth of the 

 Thames ; and within the glaciated area there are many 

 extensive tracts of land devoid of ' drift ' or other indi- 

 cations of ice-action. 



" By comparison with the phenomena displayed in the 

 North American continent, English glacial geology must 

 seem puny and insignificant ; but, just as with the feat- 

 ures of the ' Solid Geology/ we have compressed within 

 the narrow limits of our isles an epitome of the features 

 which across the Atlantic require a continent for their 

 exposition. It has resulted from this concentration that 

 English geology requires a much closer and more minute 

 investigation. And the difficulty which has been experi- 

 enced by glacial geologists of dealing with an involved 

 series of facts has, in the absence of any clue leading to the 

 co-ordination of a vast series of more or less disconnected 

 observations, resulted in the adoption, to meet certain local 

 anomalies, of explanations which were very difficult if not 

 impossible of reconciliation with facts observed in adjacent 

 areas. Thus, to account for shell-bearing drift extending 

 up to the water-shed on one side of a lofty range of hills, a 

 submergence of the land to a depth of 1,400 feet has been 

 postulated ; leaving for independent explanation the fact, 

 that the opposite slopes of the hills and the low ground 

 beyond were absolutely destitute of drift or of any evidence 

 of marine action. 



" In the following pages I must adopt a somewhat dog- 

 matic tone, in order to confine myself within the limits of 

 space which are imposed ; and trust rather to the cohesion 

 and consistency of the explanations offered and to a few 

 pregnant facts than to the weighing and contrasting of 

 rival theories. 



" The facts point conclusively to the action in the Brit- 

 ish Isles of a series of glaciers radiating outward from the 

 great hill chains or clusters, and, as the refrigeration pro- 

 gressed, becoming confluent and moving though in the 



