82 



PKOCEEDINGS OF THE GEOLOGHCAL SOCIETY. 



In the middle of the Sangatte series a line of chalk boulders, de- 

 posited at an angle of 12°, is shown in some places. At about half a 



-pig. 14. — Section of Cliff East of Freshwater Gate, Isle of Wight, 



Eig. 15. — Section of Sangatte Cliff from the heach. 



mile from this point Mr. Prestwich found, just above high-water 

 mark, abundance of freshwater shells of living species in a fine tran- 

 quilly deposited marl covered by 50 feet of gravel, continuous with 

 the upper 30 ft. of the gravel shown in fig. 15. The slope of the 

 covering bed of gravel {e) is not more than 1° or 2°. There is very 

 high ground at the back of this section (which is near Cape Blanc- 

 nez), from which the chalk and gravel were derived and thrown over 

 the ancient chalk-cliff 80 feet high. 



Near the village of Sangatte the covering gravel reaches high- 

 water mark, and the whole of the middle series intercalated between 

 the basement gravel and the covering gravel is seen. 



While the materials of the gravel at Sangatte are principally 

 brought over the cliff from the high land, they are interstratified 

 with an ordinary beach and with a lacustrine deposit formed at the 

 same time within a few feet of the present level of high water. 



A similar beach, or a similar lacustrine deposit, might be formed 



