Yol. 65.] THE BOULDERS OF THE CAMBRIDGE DRIFT. 247 



memoirs and papers, and no references have been given to general 

 text-books : — 



T. G-. Bonney. 'Notes on the Eoslyn Hill Clay-Pit' Geol. Mag. 1872, 



p. 403; and Proc. Carob. Phil. Soc. pt. xiii. vol. ii (1872) p. 268. 

 A. J. Jukes-Browne. Geological Map of the Neighbourhood of Cambridge, 



1874. 

 T. G. Bonney. ' Cambridgeshire Geology ' Sro, Cambridge, 1875. 

 A. J. Jukes-Browne. ' The Post-Tertiary Deposits of Cambridgeshire ' 



(Sedgwick Prize Essay for 1876) 1878. 

 W. H. Penning & A. J. Jukes-Browne. ' The Geology of the Neighbour- 

 hood of Cambridge' (Explanation of Quarter-Sheet 51 S.W., &c.) 



Mem. Geol. Surv. 1881. 

 W. Wiiitaker. ' On a Deep Channel of Drift in the Valley of the Cam 



(Essex)' Quart. Jotirn. Geol. Soc. vol. xlvi (1890) p. 333. 

 A. Harker. ' Norwegian Bocks in the English Boulder-Clays' Geol. Mag. 



1894, p. 334. 

 H. H. Howorth. 'The Chalky Clay of the Fenland, &c.' Quart. Journ. 



Geol. Soc. vol. li (1895) p. 504. 

 H. H. Howorth. 'Erratic Boulders & Foreign Stones in the Dri It-Deposits 



of Eastern England, &c.' Geol. Mag. 1897, pp. 123 & 153. 

 R B. C. Reed. ' Handbook to the Geology of Cambridgeshire ' 1*97- 

 F. R. C. Reed. ' Note on a Large Boulder at Wimpole Hall (Cambs.) ' Geol. 



Mag. 1898, p. 267. 

 H. B. Woodward. 'On some Disturbances iu the Chalk near Royston 



(Hertfordshire)' Quart. Journ. Geol. Soc. vol. lix (1903) p. 362. 

 W. G. Fearnsides. ' Handbook to the Natural History of Cambridgeshire' 



(Ed. Marr & Shipley) Brit. Assoc. (Cambridge) 1904, p. 37. 

 R. H. Rastall. ' On Boulders from the Cambridge District, collected by 



the Sedgwick Club' Rep. Brit. Assoc. (Cambridge) 1904, p. 571; see 



also Geol. Mag. 1904, p. 542. 

 T. G. Bonney. 'On the Relations of the Chalk & Boulder-Clay near 



Royston (Hertfordshire)' Quart. Journ. Geol. Soc. vol. lxii (1906) 



p. 491. 

 W. Hill. 'On a Deep Channel of Drift at Hitchin (Hertfordshire) ' Quart. 



Journ. Geol. Soc. vol. lxiv (1908) p. S. 



III. Method of Investigation. 



Generally speaking, large boulders are rare in the district round 

 Cambridge, and very few are to be seen scattered over the surface ; 

 this rarity may be due to the fact that they never existed, but 

 much more probably to artificial causes. As is well known, 

 building-stone is non-existent iu the immediate neighbourhood, and 

 it is only natural that for the rougher kinds of building and for 

 pavements any hard material which lay close at hand would be 

 utilized. In the town of Cambridge and in all the surrounding 

 villages there are to be seen great stretches of cobble-stone pave- 

 ment, consisting chiefly of rounded and subangular blocks of various 

 kinds and often of considerable size. Many of these pavements 

 evidently date from a time when transport was costly and difficult, 

 and it seems highly probable that the material was obtained 

 close at hand. Now, the only conceivable source for these stones 

 is the Drift or its derivatives, and the total bulk of them must be 

 enormous. That this is the true cause of the absence of surface- 



s2 



