SECTIONAL TRANSACTIONS.— C. 347 



(a) Mr. Warren. — The Lower TJiames. 



The paper discusses the broader principles of the formation of the river terraces, 

 and of the relative parts played by the process of erosion and the process of deposition. 



As the Pleistocene river deposits are markedly unlike the river deposits of the 

 present day, or of the Neolithic and Bronze Ages, it is inferred that the Pleistocene 

 rivers were equally unlike the present rivers. Although that is familiarly known, its 

 consequences have not always been sufficiently kept in view in theoretical problems. 



It is important to obtain some estimate of the depth of water that was present 

 in the Pleistocene rivers, and never to overlook the contemporary formation of 

 deposits upon the flood-plain and in the river-bed. Although of different level, such 

 deposits must, under the conditions specified, be of one epoch. The succession of the 

 Palaeolithic industries is questioned by many geologists, but it is suggested that if 

 the industries be taken in conjunction with this modified view of the terraces, the 

 two become mutually illuminating. 



In the Maidenhead district, Mr. Treacher has identified gravels which are inter- 

 mediate between the Boyne Hill and Taplow terraces. These are named the Furze 

 Piatt gravels, and it is these exclusively that yield the Palaeolithic industry of which 

 the Gray's Inn Lane implement found in a.d. 1690 is a typical example. The 

 original Boyne Hill gravels appear to yield only the industry which was called the 

 ' oldest class ' by Worthington Smith. 



The author concludes that the gravels yielding the Gray's Inn Lane industry 

 throughout the Thames Valley, even although not upon one level, should be separated 

 from both the Boyne Hill and the Taplow terraces, and placed in the Furze Piatt 

 stage. 



{b) Dr. K. S. Sandford. — Features of the River Gravels of the Upper 

 Thames Basin. 



The highest river-terrace (80-100 ft. above present river-level) is younger than the 

 various deposits grouped as Plateau Drift, which contain large quantities of erratic 

 material not infrequently bearing glacial striae. The erratic material thus reappears 

 in the river- terraces. There can be no doubt that there was a glaciation — the maximum 

 development in the Southern Midlands — before the High Terrace was formed. The 

 High Terrace contains a ' warm fauna ' (as at Handborough), including a variety of 

 Elephants, and is probably to be correlated with the High Terrace of the Lower 

 Thames. 



The rivers deepened their beds some 50 feet, and in a terrace, now fragmentary, 

 rolled Chellean implements have been found ; the deepening process was continued 

 almost to present river-level, and a widespread terrace at about 15 feet deposited. 

 This contains a ' cold fauna ' at the base — abundant mammoth, with woolly 

 rhinoceros and bison, but no reindeer — covered unconformably by gravels with a well- 

 marked 'warm fauna ' (Elephas antiquus. Hippopotamus, Corbicida fluminalis, etc.). 



Rare Upper Acheulean implements have been found in this double terrace. A 

 period of aggradation seems to have followed, for the deposits are next found in a 

 channel cut through the older terrace (about 40-50 feet) at Wolvercote. The ' warm 

 fauna ' remains, with unworn implements of Upper Acheulean and Micoque industries ; 

 sands with temperate shells follow, then a peat (now destroyed) of temperate or cold 

 temperate character. Lastly follow thick clays, completing the filling of the channel, 

 in which flakes have rarely been found (probably Mousterian), and one antler of 

 reindeer. The clays are covered and disturbed by ' frozen-soil gravels ' — a complete 

 change of climate being marked as we pass from bottom to top of the channel. Lastly 

 the rivers deepened their channels : the surface of the 15-feet terrace was disturbed 

 in the process and capped by slight thicknesses of gravel. A channel was cut some 

 30 feet below the present rivers and was subsequently filled with sand and gravel in 

 which the mammoth seems to occur again. This downward movement is most 

 probably contemporary with the frozen-soil gravels and of Upper Palaeolithic age. 



Professor Marr was interested in the ' cold ' fauna below the Hippopotamus- 

 bearing beds. He thought it possible that the apparent absence of the former in 

 the district was due to actual occupation of that area by ice. 



Mr. Llewellyn Treacher congratulated Mr. Warren on' ntroducing the term 

 Gray's Inn Lane Type to describe a set of implements which -s also characteristic of 

 the Furze Piatt gravels in the Middle Thames Valley from Reading to Maidenhead 



