Vol. 65.] THE BOULDERS OF THE CAMBRIDGE DRIFT. 259 



made by Mr. B. Schon, M.A., F.G.S., of Trinity College, Cambridge, 

 to whom we take this opportunity of expressing our thanks. The 

 greater part of these specimens came from gravel-pits in the neigh- 

 bourhood of Bedford, and a smaller number from Fenny Stratford. 

 Although not actually obtained from the district dealt with in the 

 present paper, this collection is valuable as showing the westward 

 extension of ice from the North Sea. 



Bedford, Kempston, Biddenham, Clapham, etc: 124 

 specimens. — The Scandinavian petrographical province is repre- 

 sented by six fine specimens of rhomb-porphyry, some of unusually 

 large size, one nordmarkite, and two felspathic grits of Sparagmite 

 type. Porphyry x is very abundant throughout the district. The 

 rocks of Central Scotland are represented by one Forfarshire 

 porphyry and three or four orthophyres of North Berwick type. 

 The South of Scotland and the Cheviot district are strongly re- 

 presented. The usual dolerites and basalts occur. An important 

 fact is the occurrence here of Red Chalk and bored Gryphseas. 

 Metamorphic rocks are common. 



Fenny Stratford: 14 specimens. — The chief types repre- 

 sented here are porphyry x, Cheviot dykes, and bored Gryplueas. 



The collection from this locality is too small to enable any 

 conclusions of value to be drawn from it, bur the occurrence of 

 porphyry x so far west is worth noticing. 



VI. General Remarks. 



The abundance of Scandinavian rocks as boulders'in the Drifts of 

 Eastern England is well known, and it is not necessary to enlarge 

 upon the occurrence of nordmarkite, laurvikite, rhomb-porphyry, 

 etc., in Lincolnshire and Norfolk, except in so far as this affords 

 general confirmation of our conclusions. "We have, therefore, paid 

 no attention to the boulders of Eastern Norfolk, so well seen at 

 Cromer, Sheringham, etc. Since, however, there is some evidence 

 that part at least of the Cambridge ice came in by the "Wash, 

 bringing with it Red Chalk and bored Gryphaeas from the bed of the 

 North Sea, it was considered desirable to pay some attention to the 

 boulder-assemblage found at Hunstanton. AVe have examined a 

 collection of boulders from this locality, made by Mr. C. E. Gray, of 

 the Sedgwick Museum, and in this many of the most important 

 Cambridge types are represented. The collection includes 15 rhomb- 

 porphyries, 2 porphyries of x type, Cheviot dyke- and lava-rocks ; 

 and, most important of all, two good specimens of the Buchan 

 Ness dyke-rock (one of the latter was collected by Prof. Hughes). 

 Some other specimens are indeterminable, but present a general 

 resemblance to the Scottish lavas of Old Red Sandstone age. This 

 evidence, so far as it goes, is very satisfactory, and agrees well 

 with the general character of the Cambridge boulders. 



