12 



as communicated by Prof. Sedgwick to the Annals of Philo- 

 sophy, Ser. 2, Vols. ix. and X. (See p. 4.) 



In the first of these he takes the fenlands of Cambridgeshire 

 as a typical example of the alluvial deposits, and briefly de- 

 scribes some of their physical features, characterising them gene- 

 rally as exhibiting several levels of distinct fenny regions, 

 interrupted here and there by extensive protuberances of dilu- 

 vial gravel. 



Under the head of diluvial formations he remarks that "the 

 true relations of the diluvial detritus are beautifully exemplified 

 on the flanks of the Chalk Hills which skirt the south-east side 



of the marsh-lands above described" "it is constantly seen 



to rise out from beneath all the alluvial lands, and sometimes 

 to lie in scattered masses on the very top of the Chalk Downs." 



The Diluvium he mentions more particularly in the second 

 communication, where, as we have already seen, he divides the 

 deposits into two classes ; among the Gog-Magog gravels he 

 speaks of finding rolled masses of granite and porphyry pebbles 

 resembling those in the New Red Sandstone, masses of trap and 

 mountain-limestone, and a fine series derived fram the Oolitic 

 formations. 



1836. Dr Fitton, in his well-known memoir on the Strata 

 between the Chalk and the Oxford Oolite, makes some mention 

 of the Cambridge Drifts at p. 303, of Trans. Geol. Soc. Ser. 2. 

 Vol. IV. He says, "Another general circumstance which charac- 

 terises the north-east of Cambridgeshire is the great extent and 

 varied composition of the transported masses with which the 

 strata are often invested. This superficial deposit includes... 

 rounded pebbles of chalk in such abundance as to form a very 

 large proportion of the entire mass. With these are certain 

 fossils...Belemnites and Gryphites, portions of skeletons of 

 Elephants, Rhinoceros, Hippopotamus, Deer, Gigantic Oxen 

 and Horse. The mass thus composed forms many of the hills 

 on the borders of Cambridge and Essex, and occupies a great 

 part of the platform which runs along the confines ol the former 

 county and Huntingdonshire; a brown variety of it obscures the 

 junction of Gault and Lower Greensand, W. of Cambridge, 

 forming an upland which extends from Bourne by Toft and 

 Hardwick to Dry Drayton, where it declines into the plain." 



