Reiwrts & Proceedings — Geological Society of London. 45 



This paper deals with the deposits in the immediate vicinity of 

 Cambridge, and contains new records of sections, fossils, and 

 implements. It is pointed out that owing to alternating periods of 

 erosion and aggradation, relative height above sea-level is not a 

 trustworthy index of antiquity, and modifications of the classification 

 proposed by W. Penning and A. J. Jukes-Browne are indicated. 



The author suggests the following chronological sequence, in 

 descending order : — 



Feet. 



1. Barnwell Station Beds ..... 20 



2. Newer Downing Site Beds ..... 3-5 



3. Newer Barnwell Village Beds .... 4-5 



4. Huntingdon Eoad Clays ..... 70 



5. Observatory Beds ...... 85 



6. Corbicula Gravels (Barnwell village, etc.) . . 30 



The figures on the right 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 3 are 

 of different ages, although the deposition of the beds 6 below those 

 of series 3, where they occur together, and the occurrence of 

 Hippoj)otamus and Belgrandia marginata with Corbicula suggest 

 an early date for these Corbicula-heaiiug 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 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 

 moUusca and mammalia are very rare in these beds. The Huntingdon 

 Road Clays require 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 Palaeolithic 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 molluscan 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 Palaeolithic beds to the glacial accumulations, 

 and also to the marine beds of March and the Nar Valley. 



