IN THE ISLE OF PORTLAND AND AROUND WEYMOUTH. 45 



coast, in the Channel Islands, and on the coast of Cotentin, says of 

 them : — " These beds, wherever found, are remarkably uniform in 

 their general appearance and composition : they consist of fine earthy 

 matter, such as would result from the decomposition of the rocks 

 of the place ; mixed with this are fragments of rocks of all sizes, 

 ranging up to blocks of considerable dimensions : the fragments are 

 obviously smaller in the upper portion of these accumulations than 

 in the lower. In places where the slope of the land is at a small 

 angle, the " head " is mostly earthy, and of small amount ; where it 

 is steep, or rocky, it becomes in proportion thick and fragmentary : 

 the component fragments will, in this case, be seen to have been 

 derived in every instance from the masses of rock immediately over- 

 hanging — the materials are always strictly local as to origin. 



" These accumulations, as seen in cliff-sections and at short dis- 

 tances, present an appearance of horizontal arrangement; closer 

 examination, however, shows that this has nothing of the character 

 of subaqueous arrangement : another very obvious feature is, that 

 the fragments are all perfectly sharp and angular — no specimens of 

 included waterworn rock are ever found." After a general survey 

 of the whole area, Mr. Godwin- Austen concludes that they are of 

 subaerial origin, and are due to the action of great cold — not neces- 

 sarily that of a glacial period, but arising from elevation of the land ; 

 and he thus tersely sums up : — " These phenomena so exactly accord 

 with what is to be observed in all regions of excessive temperatures, 

 whether resulting from geographical position or from altitude, they 

 are so totally beyond the power of any present agencies, that it seems 

 absolutely necessary to call in the operation of cold to adequately 

 account for them. Many considerations oppose the possibility of low 

 temperature along the parallel of 50° N.E., whence these observa- 

 tions have been derived ; and the only physical condition which I can 

 imagine sufficient to account for the fragmentary detritus generally 

 of the whole of those areas from which I have borrowed illus- 

 trations, is that of an elevation of great amount, such as would place 

 the whole of the higher portions of this country in regions of excessive 

 cold." 



At about the same period I described a similar deposit at Sangatte 

 Cliff* much in the same terms as regards its composition as Mr. 

 Godwin -Austen, but came to the conclusion, after examining this 

 and also the Brighton bed, that the acting force had been subaqueous 

 rather than subaerial, and that it was of short duration and violent ; 

 but I did not then venture to speculate on the causes which led to 

 the result or the exact mode of operation. 



At that time neither Mr. Godwin-Austen nor I had detected any 

 shells in these beds. I subsequentlyf found land-shells of the most 

 delicate structure in the Sangatte deposit. 



While in the main I agree with my friend as to the condition of 

 the debris, I do not agree with him on some points of structure. So 



* " On the Drift at Sangatte Cliff, near Calais." Quart. Journ. Geol. Soc. vol. 

 rii. p. 274, 1851. 



t Quart. Journ. Geol. Soc. vol. xxi. p. 440, 1865. 



