Henry Dewey — Raised Beach of North Devon. 161 



' mammoth ' fauna. Lower down stream, near Gravesend, a tributary- 

 has cut through the 100 foot gravels of the main river a valley some 

 40 feet deep, which is partially infilled with Coombe Rock. In 

 this deposit many thousands of palseoliths have been found. They 

 are identical with the ' Levallois flakes' of French authors, and occur 

 much as they were left by their manufacturers before the downrush 

 of Coombe Rock overwhelmed them. The evidence derived, then, 

 from the Thames Valley is that after the Chalky Boulder-clay had been 

 deposited the Thames cut a deep valley in several stages. The highest 

 of these contains (1) a fauna indicating a warm temperate climate, and 

 (2) Chelles palseoliths. After a period of uplift another terrace was 

 cut in which animals of a cold climate are found in association 

 with Le Moustier palseoliths, St. Acheul man living in the interim. 

 Expressed in a tabular form we have the following sequence : — 



Le Moustier period = Coombe Eock 1 / -, . , ,^ 



St. Acheul period |(advancmg cold). 



Chelles period (temperate). 

 Chalky Boulder-clay (Arctic). 



This sequence of climates is identical with that indicated by the 

 raised beach deposits, but to make it clear the several stages are 

 shown in the following table — 



Arctic 

 Advancing cold . 



Warm temperate j 

 Ketreating cold . 



Arctic 



Palaeolithic 

 Period. 



Le Moustier - 



St. Acheul \ 

 Chelles V 



Strepy J 



Eiver Thames. 



Ponders End deposits 

 Combe Eock \ 



50 ft. terrace gravels / 



100 ft. terrace gravels 

 Chalky Boulder-clay 



Eaised Beaches. 



Boulder-clay 

 Head 



Cemented sands and 

 cave sands 



Erratics of raised 

 beach 



Conclusions. 



1. That the deposits overlying the raised beaches were accumulated 

 during a period of variable climate, being Arctic at first, then 

 ameliorating to warm temperate, and finally returning to Arctic. 



2. During the inter- Arctic period early Palaeolithic man lived. 

 He is later than the Chalky Boulder-clay and raised beach and earlier 

 than the Boulder-clay of Glamorgan and Southern Ireland. 



3. These conclusions accord with those of Continental authors, 

 a brief summary of which is appended. 



Summary of Conclusions of Continental Observers. 

 Professor Comment ^ has worked out the relations of the valley 

 deposits of the River Sorame to the stages of culture of Palaeolithic 



■^ " Les Gisements paleolithiques d' Abbeville," Excursion de la Soci^te 

 geologique du Nord et de la Faculte des Sciences de Lille, a Abbeville, le 

 11 Juin, 1910; and "Comparaison des Limons Beiges et Etrangers," Ann. Soc. 

 geol. Belg., tom. xxxix, 1912. 



DECADE V. — VOL. X. — NO. TX . 11 



