400 PROFESSOR HUGHES 



showing the distribution of the soils, subsoils, and underlying 

 beds referred to in the explanation offered. 



This might have been done with much greater accuracy 

 had a record been kept of what has been exposed to view even 

 in the last twenty-five years, or were there any possibility of 

 comparing the groups of remains found in the different areas, 

 but, with the data available, it is not so easy. 



However, I have endeavoured to sketch in what I have 

 observed myself, and hope that it may be of help to others who 

 will follow up the work. 



I have traced the various deposits on the plan of Cambridge 

 by Braunius (Plate XXVIII), notwithstanding its inaccuracy, 

 as it shows the area over which the houses of the town 

 extended in 1575, and the distribution of the colleges outside 

 that area. 



The description of this plan furnishes an opportunity of 

 discussing in greater detail certain features, many of which 

 can still be observed, and of placing on record some of the 

 sections which have been sunk through the natural and artifi- 

 cial accumulations over the area, and thus offering proofs of 

 the generalised statements made above in explanation of the 

 views put forward as to the growth of the Town and Uni- 

 versity. 



I have traced the margin of the alluvium (Al), and shown 

 the part (A2) over which the level has been raised by carrying 

 rubbish on to it. I have indicated (G2) the margin of gravel 

 which sloped down to the level of the alluvium and passed 

 under it. As this was the portion immediately adjoining the 

 higher ground on which the town was built, it was of course 

 the part first levelled up, and it was only by degrees that the 

 made ground extended over the edge of the alluvium also. 



The old river-courses (G3), with terraces which were formed 

 during the deposition of the gravel, or subsequently to the 

 deposition of the main mass, but which do not cut through the 

 gravel, do affect the water-levels, and the suitability of the 

 area for houses. G, is gravel at or near the surface. 



The modern town has extended over the higher part of the 

 gravel, which runs from Barnwell by Parker's Piece to the 



