410 MR. G. "NV. LAMPLrGH ON THE 



" ii. Most of the granitic. p:rieissie, and crystalline schistose rocks 

 are referred with prohahility to the same source. 



" iii. Other boulders have been furnished by the northern and 

 eastern ])arts of the English Lake District. 



*' iv. Others have been derived from Teesdale ; and 



"v. Others again have come from the Cheviot Hills and the 

 southern part of Scotland " *. 



It is probable, however, that these boulders have not all been 

 carried direct from the place of their origin to their present position 

 by land-ice. We have such convincing evidence that portions of 

 a boulder-strewn sea-bed t were, in some fashion or other, torn up 

 and carried forward, with all their debris, during the formation of 

 the Basement Cla}', that it is evident the transportation of many of 

 these blocks may have been a very com})lex matter. They may have 

 been carried far by floating ice, and have rested long on the sea- 

 bottom before being finally removed and mingled with the material 

 amid which we now find them J. 



My table shows in most points a fundamental agreement between 

 the different lists ; the proportion of far-travelled igneous and raeta- 

 morphic rocks remains always very low and yet has the narrowest 

 range of variation ; blocks from the Carboniferous are always far 

 more numerous than we might expect, considering the distance of 

 the localities from the borders of that system, which are eighty or a 

 hundred miles distant; and if we eliminate the effect of the varying 

 number of the Secondaries in estimating the proportion, we shall 

 find that this remains fairly constant for the Carboniferous rocks 

 also. It is the Secondary rocks which form the unstable factor of 

 the lists, both in proportion and in composition ; and the strikingly 

 low percentage of these rocks on FJamborough Head demands 

 explanation. It is no doubt due to the bold eastward protrusion 

 of the headland obliquely to the general direction of the ice- 

 movement, a point which will be further discussed in the final part 

 of this paper. 



YI. CLAssiFiCATioisr or THE Deifts. 



From the foregoing descriptions it will be evident that the beds 

 above the Chalk on the headland may be conveniently arranged 

 under the following heads : — 



1. Alluvial wash, freshwater marls. &o. Recent. 



2h, 2c. Late-Glacial gravels, brick-earth, and Boalder-clay. ^ 



8, 3 a. Upper Boulder-clay. | 



36,3c. Iiiterniediate Series; stratified beds, with bands of I p, • , 

 Boulder-clay. [ 



4. Basement Boulder-clay. | 



.f). Chalky Rubble. J 



A, B, 0. " Infra-Glacial " beds of Sewerby and Speeton. 



* Op. cit. vol. xi. p. 422. 



t See Quart. Journ. Geol. Soc. vol. xl. (1884) p. 317. 



\ Mr. Clement Reid observes the same conditions with resjiect to the 

 boulders in the Cromer Till, Geol. Survey Mem. ' Cromer,' p. CO. 



