JST. 47.] FOSSIL ELEPHANTS. 131 



we shall at all events be able to exhibit a yet more valuable, 

 because rarer, array of figures and facts. . . . 



You will find a notice by Tournal of bones adhering to the 

 roof in the 2nd vol. ' Bull. Soc. Geol.,' p. 381 ; and again by 

 Teissier, same vol., pp. 22 and 56. Marcel de Serres also some- 

 where notices the same fact I think in a cavern in the Pyrenees. 

 I will try and find out the reference. 



On Saturday I was at Erith, where it seems to me the E. 

 primigenius and E. antiquus occur together. On Sunday I saw 

 only some Tertiary sections. 



J. Prestwich to Sir Charles Lyell. 28, 6, 59. 



MY DEAR SIR CHARLES, A main object of our visit to Erith 

 was to see whether the E. primigenius and E. antiquus occur 

 there in different beds. We found nothing in situ to settle the 

 question ; but a careful inspection of Mr Spurrell's collection 

 leads me to the belief that no separation can at present be 

 made. The greater number of teeth in Mr Spurrell's collection 

 are of the E. primigenius. I saw only two of the E. antiquus. 

 In universal character no distinction could be made. Still, the 

 evidence is not complete. The Menchecourt species is, however, 

 decidedly the E. primigenius; and then we have the Cyrena 

 fluminalis. As to the question you ask me about the Shackle- 

 well Gravel, it is a question I have asked myself the last fifteen 

 years without being able to feel certain about an answer. My 

 opinion long inclined to the belief that the Grays deposit is 

 newer than the Boulder Clay ; these other gravels of the Thames 

 valley are consequently of the same recent age. Of late I have 

 not felt so sure. I find the Boulder Clay sweeping down to a 

 very low level in Essex. I find also that many rock specimens 

 I referred to the Boulder Clay may also be referred to the great 

 Western Drift, and I am not yet satisfied that I have got the 

 correlation of these two drifts. I hope this summer to be able 

 to work up all my evidence and go through all my collections. 

 I must also again visit a few places in the eastern counties. I 

 shall then begin with the Clay and work upwards, when I hope 

 to find the difficulties which now perplex me disappear as they 

 are handled in right succession. My impression at present is 



