J3T. 48.] BOULDER CLAY AT GOWER. 151 



Kaised Beach period, and that the elephant and other remains 

 have been subsequently introduced, we shall arrive at the inter- 

 esting and curious conclusion that this particular group of mam- 

 malia lived after the formation of those beaches beaches which 

 have always been considered as of very recent origin, as they 

 contain nothing, so far as they have been examined, but the 

 commonest shells of our coasts. At the same time, it is to be 

 observed that they contain but very few species, and that no 

 complete and thorough investigation of them has yet been 

 made. With regard to your suggestion in connection with the 

 two species of elephant, I must confess that I saw nothing in 

 the physical features of the scene, during the somewhat hurried 

 and imperfect view I had of it, to lead me to suppose that the 

 caves, or rather their inhabitants, might be referred to two 

 periods. I should hardly have hazarded this opinion without a 

 further examination of the district ; but I give it for what it is 

 worth, and waiting further data. 



With respect to the point I had particularly in view, viz., the 

 relation of the Gower caves to the Boulder Clay, I am unable 

 as yet to form a decided opinion. I got the Boulder Clay within 

 a mile of the raised beach, but on opposite sides of the point of 

 Khos Sili. It spreads from the sea-shore to, as you are aware, 

 the top of the hills. In Khos Sili Bay I found intercalated in it, 

 at an elevation almost exactly corresponding to the raised beach 

 on the opposite side of the promontory, a bed of shingle con- 

 taining several species of recent shells, but not one of the 

 species occurring in the raised beach. Yet the two would appear 

 to be synchronous : the difference might arise from the one being 

 on an exposed and open coast, and the other in a sheltered 

 bay. The subject requires a fuller and more lengthened 

 inquiry. 



J. Prestwich to Sir Charles Lyell. 23rd May 1860. 



MY DEAR SIR CHARLES, I have been considering some of the 

 questions you propose to me, for the purpose of adding a note 

 to Falconer's paper, which he reads at the next meeting. I 

 hope to finish it to-day or to-morrow, and will send you a 

 copy of it. 



The Boulder Clay seems to reach within two miles of the 



