CHAPTER TWELVE 



THE GROWTH OF CAMBRIDGE 

 By J. B. Mitchell, m.a. 



Two ESSENTIAL ELEMENTS NEED STRESS IN THE SITUATION 

 of Cambridge : its position on the Cam at the jmiction of Fenland 

 and Upland and its relation to the open chalk country and gravel 

 terraces controlling the land routes. The Cam, navigable from Lynn to 

 Cambridge, was a main artery of communication through the Fenland: 

 sea-going vessels were still discharging their goods at Cambridge quays and 

 hithes in 1295, while river traffic remained of great importance until the 

 competition of the railways ruined the watermen in the nineteenth 

 century. Cambridge also owes much to its land routes. A slight transverse 

 fold in the south-easterly dipping chalk throws a fmger from the chalk, 

 escarpment north-west across the valley of the Cam,' the severed tip of 

 tliis fmger forming the chalk outher of Castle Hill. This ridge capped and 

 extended by gravel-spreads provided a ford across the river, and constituted 

 a south-east — ^north-west land route from East Anglia to the Midlands 

 crossing the north-east — south-west river route at Cambridge. The main 

 Roman road of the area, the Via Devana, exacdy followed this ridge: the ■ 

 modern roads south of the river approach along the gravel terraces of the 

 valley but continue north-west along the ridge to-day (Fig. 37).^ 



The site itself, where chalk and gravel approach the river, afforded the 

 essentials of solid banks for bridging and dry ground for building, and was 

 partially protected by the sweep of the river and its marshes. The distribu- 

 tion of the gravels, which largely determine the minor elevations (com- 

 pare Figs. 37 and 3 8), 3 assume a great importance on a site as low and liable 

 to flood as Cambridge. The gravels within the meander consist essentially 

 of the Higher Terrace gravels of Trumpington to the west and of Barnwell 

 to the east rising to 50 ft., separated by a spread of Lower and Intermediate 

 Terrace gravels lying approximately at 30 ft. o.d. Along the centre of the 



' I.e. the Gogmagog Hills which are shown up clearly in Fig. 8. 



^ On Fig. 37, the 100 ft., 50 ft. and 20 ft. contours have been traced from the 

 Ordnance Survey 6 in . sheets : form lines, at 10 ft. intervals, have been interpolated 

 from the O.S. 25 in. plans (1925 edition). The unequal intervals of the layer colouring 

 have been deliberately chosen for comparison with the built-up areas. 



3 Fig. 38 is based on the i in. Geological Survey sheets (Drift edition) of the area. 

 For access to the 6 in. map of the southern part of the area, and to a map of the 

 Geology of Cambridge, by A. J. Jukes-Brown, I am indebted to the Director of the 

 Geological Survey, 



