440 PROCEEDINGS OF XHE GEOLOGICAL SOCIETY. [May 24, 



The following communications were read : — 



1. Additional Observations on the Raised Beach of Sangatte 

 with reference to the Date of the English Channel, and the Pre- 

 sence of Loess in the Cliff Section. Bj J. Pkestwich, Esq., 

 F.R.S., Treas. G.S. * 



In my paper on the Loess and Quaternary beds of the north of 

 France and south-east of England, I expressed an opinion that the 

 break in the land between France and England was not the result 

 of the last geological change f, but that the Channel existed at the 

 period of the formation of the low-level gravels of the Somme and 

 Thames valleys, and probably at the period of the high-level gravels. 

 The argument was based upon the position of analogous beds at 

 places on both sides of the Channel, upon the contour and slope of the 

 land, and the direction of the Sangatte and Brighton raised beaches. 

 I was not then able to give more positive evidence. I am, how- 

 ever, now in possession of facts which enable me to do so, and these 

 I will briefly lay before the Society. 



On my return last Easter from an excursion in Belgium with 

 several Fellows of this Society, I took the opportunity of revisiting 

 the Sangatte section in company with Mr. Godwin- Austen. The 

 winter storms had cleared the beach and bared the cliff, and we 

 found a long and very interesting section exposed. Our visit was 

 short. It enabled me, however, to recognize some beds very loess- 

 like in character, and to detect traces of shells in some of them. 

 "We also again noted in the underlying old sea-bed layers of a green 

 sand, which might have been derived either from some Lower Ter- 

 tiary beds or from the Greensands. 



We thence proceeded round Cape Blanc-nez, where Mr. Godwin- 

 Austen wished to see the peculiar structure of the Lower Cretaceous 

 series, whilst it gave me the opportunity of ascertaining whether the 

 old beach extended round that chalk promontory into Wissant Bay. 

 So far as we went we saw no trace of it there, but, owing to the 

 extent of the dunes around Wissant, such a beach might be entirely 

 hidden by the sands. 



On my return through Calais from Bethune a few days later, 

 I took the opportunity of paying another short visit to the cliff at 

 Sangatte for the purpose of making both a larger collection of shells 

 from the chalk rubble and loam beds and a closer examination 

 after rock specimens. 



The old beach, as I have before described, consists almost en- 

 tirely of much- worn large flint shingle, with a few rolled blocks of 

 chalk fallen from the old cliff, and with some pieces of worn Ter- 

 tiary iron-sandstone. Above the shingle, and at some short distance 

 from the foot of the old cliff, are some light- coloured sands, with 

 seams of green sand above mentioned, and subordinate beds of shingle. 



* The first notice of this beach was given by the Author in the Quart. Journ. 

 Geol. Soc. vol. vii. p. 274, 1851. 

 t Phil. Trans, for 1864, p. 301. . 



