CHAPTER II. 



LITERATURE OF THE SUBJECT. 



The occurrence of various drift deposits and superficial gravels 

 in the county of Cambridge has been noticed by many geolo- 

 gical writers since the beginning of this century. Some of 

 these authors have described important local sections, others 

 have given a general account of the distribution and relations- 

 of the several beds, and most of them have discussed at more or 

 less length the questions connected with their origin and mode 

 of formation. Before, however, we can hope to ascertain the 

 complete and correct history of the deposits under consideration, 

 it is necessary that their distribution and mode of occurrence 

 should be much more accurately known than they hitherto 

 have been ; it is therefore the object of the present essay to 

 add more facts to our stock of information on these points, and 

 to present as complete an account as possible of the accumula- 

 tions which are met with in the Cambridgeshire district; but 

 before entering on such detailed descriptions, it will certainly 

 be desirable to review what has previously been written on the 

 subject. With this view I have prepared brief abstracts of the 

 various papers and memoirs treating of the Cambridgeshire 

 drifts, arranging them in the order of their publication ; in doing 

 this I have endeavoured to avoid the description of sections 

 which would be subsequently repeated, mentioning chiefly the 

 localities described and the conclusions arrived at by the 

 several authors. 



The earliest notice I have been able to discover which refers 

 specially to the drifts of this county is from the pen of the 



