PREHISTORIC MAN IN BURMA. 333 



but, following the outline of the pieces, there is a distinct " skin," 

 or line of weathering, about one-sixteenth of an inch in depth, 

 of a lighter colour, showing considerable lapse of time since the 

 original stones were broken up. 



In his ' Prehistoric Times,' Lord Avebury points out, on 

 p. 329, with regard to flint flakes, that " those which have lain 

 in siliceous or chalky sands are more or less polished, and have 

 a beautiful glassiness of surface, very unlike that of a newly 

 broken flint. In ochreous sand, especially if argillaceous, they are 

 stained yellow, whilst in ferruginous sands and clays they assume 

 a brown colour, and in some beds they become white and porcel- 

 lanous." Now, these pieces are nearly all either almost white or 

 light cream-colour, though some are about the colour of honey ; 

 whereas, had they lain in the red band of conglomerate since it 

 was deposited, they would surely have been much darker. As a 

 matter of fact, in nearly every instance in which a piece of the 

 exterior of the original stones is found, on a flake, it is seen to 

 be yellow or orange, sometimes brown, and this might give a clue 

 as to where they came from. 



There is a plateau gravel at Yenangyoung which contains 

 large rounded stones, but we could not give much time to 

 searching in it for pieces of flint ; and, though I picked up a 

 piece by the side of a cart-track, I did not at the time connect it 

 with flint chips, and threw it away, and was unable to find it 

 again. There is apparently no reason why the lumps of chert 

 found on the plateau should be brought from any distance over 

 a mile or two to the spot where they were broken up, and a 

 further search in the neighbourhood would no doubt disclose the 

 source of them. Mr. LaTouche has taken a few of the pieces 

 for microscopic examination as to their composition. 



As I have already mentioned, Mr. Oldham and others regard 

 the pieces found by Dr. Noetling, which are now in the Geological 

 Museum in Calcutta, as natural ; but, as an answer to this, in 

 the year 1897, Dr. Noetling published, in the ' Records of the 

 Geological Survey of India,' vol. xxx. part 4, p. 242, an article 

 entitled " Note on a worn Femur of Hippopotamus irravadicus, 

 Caut. & Falc, from the Lower Pliocene of Burma," in which he 

 figured and described a very fine unbroken femur, exhibiting at 

 both ends " traces of a peculiar kind of grinding." He says he 



