208 Geological Society. 
The figures on the left give the approximate height above 
sea-level. 
It is believed that Nos. 6 and 5 were formed during a period of 
aggradation, and 4-1 during one of subsequent erosion with minor 
aggradation; but it cannot be conclusively proved that 6 and 8 are 
of different ages, although the deposition of the beds 6 below those 
of series 8, where they occur together, and the occurrence of 
Hippopotamus and Belgrandia marginata with Corbicula suggest 
an early date for these Corbicula-bearing beds. 
Taking the beds in the order of reputed age, the following 
observations are noted :— 
Chellean implements have been found at low levels at Barnwell 
and Chesterton, and may belong to the beds 1. The Observatory 
Beds have -yielded abundant implements of Chellean, Acheulean, 
and early Mousterian types, the last-named apparently in deposits 
later than those containing the two first-named. Unfortunately 
mollusca and mammalia are very rare in these beds. The Hun- 
tingdon Road Clays require much further work, as only poor 
exposures have hitherto been found, and it is not clear that they 
are newer than the Observatory Beds. 
The beds referred to the Newer Barnwell Village Series contain 
abundant remains of the mammoth, woolly rhinoceros, and fairly 
numerous horse-bones. Implements associated with them suggest 
an Upper Paleolithic age. 
The Newer Downing Site Beds have yielded a cold molluscan 
fauna. They are probably somewhat earlier than the Barnwell 
Station Series, which has furnished a similar mollusean fauna, and 
also an Arctic flora, the plants of which were identified by the late 
Mr. Clement Reid. Reindeer occurs in these beds. 
The paper is chiefly a record of facts, but it is intended to be 
preliminary to a detailed survey of the Pleistocene deposits of the 
Great Ouse Basin, which are so important as throwing light upon 
the relationship of the Paleolithic beds to the glacial accumulations, 
and also to the marine beds of March and the Nar Valley. 
Appendix I, on the Non-Marine Mollusca, is supplied by Alfred 
Santer Kennard, F.G.S. and Bernard Barham Woodward, F.L.S., 
E.G.S. 
Lists are given of the non-marine mollusca from the various 
sections, with their degrees of frequency. These lists are based on 
examination of old collections and on a large amount of new 
material. Notes are appended on some of the species, and con- 
clusions as to the ages of the Cambridge gravels are given, based 
on the mollusean evidence. 
Appendix IT, on the Implements, is supplied by Miles C. Burkitt, 
WA. 
