68 Dr Marr, Suhmerc/ence and glacial climates dnrmg the 



Observatory level, but no sections are now seen in them, so we 

 may pass on to the Observatory deposits. In these shells and 

 mammalian bones are very rare, though the former have been 

 found in concretions, indicating that they once lay in the gravels, 

 but have since been dissolved. Implements are relatively abun- 

 dant, and I have found a large number during recent years. 

 Many of them are of Chellean type, others probably Acheulean, 

 but there are a large number of Mousterian type, some having 

 the facetted platform which, as shewn by M. Commont, came into 

 use in Northern France in Mousterian times. It may be noted 

 that the implements of Mousterian type are patinated differently 

 to and in a less degree than those of Chellean type, and I regard 

 the two series as of distinct ages. Either the deposits, which are 

 thick and varied in character, are of two dates, or implements 

 of different ages lying upon the surface were washed into the 

 deposits contemporaneously. This can only be settled by finding 

 a number in situ, a work of great difficulty, but the evidence is 

 in favour of the latter view. 



I may note that when a valley is being deepened implements 

 of one age only are likely to lie in abundance near the spot where 

 the gravels were accumulating, but when there is general aggra- 

 dation, the highest deposits of the delta-growth are likely to 

 receive washings of implements of various ages which have been 

 lying together, at or near the surface. In any case the age of the 

 newest gravel of a terrace will be determined by the implements 

 of latest date. 



Lying on this gravel in channels are reddish sandy loams, 

 which must have spread over the gravel, but have since been 

 destroyed by erosion except where so preserved. There is also 

 a deposit of somewhat similar loam but of a lighter colour flanking 

 the gravel at a lower level on either side. It is rarely exposed, 

 and only in shallow sections, but I believe it may be of the same 

 general date as that lying on the gravel. 



No relics have been found in it, though two implements of 

 possible Upper Palaeolithic date were found on the loam when ' 

 draining the Christ's Cricket Grouod, but they may well have ■ 

 been surface finds. Many other surface finds, some of apparent ' 

 palaeolithic type, are found on this loam belt, and will be referred i 

 to later. | 



Those gravels of the terraces of Barnwell village age, which | 

 I would refer to a date later than that of the Gorhicula gravels, I 

 are now exposed in a pit near the Milton Road and in another | 

 on the Newmarket Road near Elfleda House, 2\ miles from j 

 Cambridge. These contain a fauna differing from the Gorhicida \ 

 fauna, and including the mammoth, woolly rhinoceros, horse and 

 red deer, the horse being abundant. 



