72 SECTIONAL ADDRESSES 



bones did not represent a distinctive fauna, but included fallow-deer, 

 mammoth, and Rhinoceros leptorhinus. In a second (later) terrace of 

 brickearth lying at a few feet above river-level at Stutton, Corbicula 

 fluminalis occurred in association with other land and freshwater shells. 

 This was the first appearance of Corbicula fluminalis in East Anglia 

 since the late Pliocene (Cromer Forest-bed and Weybourn Crag), and 

 in time (post-Chellian to Upper Acheulian) appears to correspond approxi- 

 mately with its appearance elsewhere in the British area. We have no 

 evidence that it was present in England during the earlier (pre-Chalky 

 Jurassic Boulder Clay) interglacial interval. 



Our picture of East Anglia at the time of Acheulian and Early Mousterian 

 Man will be completed by a glance at the Cambridge district, at present 

 under re-examination by the officers of the Geological Survey. Already 

 available to us, however, are the valuable results collected over a 

 period of years by Prof. J. E. Marr, Prof. W. B. R. King, and the 

 Cambridge school. In this district the Great Chalky Boulder Clay 

 covers much of the higher ground, the river deposits being of later date, 

 with the possible though not probable exception of the Barrington 

 gravels. It is important to note that the Great Chalky Boulder Clay 

 Ice retreated sufficiently from the area of the Wash to permit the Cam 

 and Ouse to flow northwards into an early representative of the North 

 Sea, and to allow the warm-water mollusc Corbicula fluminalis to re- 

 establish itself at numerous localities in the area. Prof. Marr shows 

 that aggradation of the valleys took place after the glaciation and re- 

 treat of the ice, the climate being at first rather warm, but later becoming 

 cooler. During this stage, valley-gravels such as the Lower Barnwell 

 Village Beds and lower evenly-bedded gravels of the Traveller's Rest 

 Pit were formed ; they contain worn Chellian and fresh Acheulian 

 implements, together with Corbicula fluminalis and remains of hippo- 

 potamus. Succeeding these deposits are the unevenly-bedded gravels 

 of the Traveller's Rest Pit, containing what appear to be La Micoque 

 and Early Mousterian industries. It is Prof. Marr's belief that during 

 this time of aggradation marine and freshwater conditions alternated 

 in the lower part of the area of the Ouse drainage — the deltaic tracts 

 of the March-Nar sea. Dr. J. D. Solomon, on the other hand, is in- 

 clined to refer the interdigitated marine and freshwater deposits to a 

 later stage. 



Resting upon the Early Mousterian gravels in Cambridgeshire is a 

 deposit similar to that already referred to as Upper Boulder Clay, Upper 

 Chalky Drift or Trail. ^ A subsequent period of erosion with minor 

 periods of aggradation intervened, resulting in the formation of, first, 

 the upper evenly-bedded gravels of the Traveller's Rest Pit, and later 

 the Upper Barnwell Village and Barnwell Station Beds with a cold fauna, 

 but without implements. 



From the surface-deposits of the district have been recorded Aurig- 

 nacian, Solutrian, Magdalenian and Azilio-Tardenoisian implements, 



' Mr. S. Hazzledine Warren in 1924 suggested that the Trail of the Thames 

 basin was of post-Mousterian age, but thought that it might be as late as 

 Magdalenian. 



