416 J. Reid Moir — Striations upon Flint. 



Anker's Pit. 

 Gr 

 Fa 

 Series 1 3. Stratified gravel. 

 I 4. 



f 1. Gravelly loam. 

 Post-Glacial I 2. False-bedded sand. 



Clay, 2 to 48 inches. 

 f 5. Gravel (late-glacial) and clay containing 

 Glacial | palaeoliths and remains of horse and 



(Pleistocene) ~1 oi Elejihas j^rimigenms with eria,tics. 



{. 6. Stratified gravel with erratics. 

 7. Oxford Clay. 



The deposits seen in Rippon's Pit may, I think, be taken as the 

 equivalents of the upper three or four beds in Anker's Pit, while 

 the lower series (5, 6) would seem to represent the succession in the 

 pits of the Loudon Brick Company, j^os. 1 and 4. There is much 

 " contemporaneous erosion and filling-up " ' in liippon's Pit. 



At No. 1 Pit (Old Pletton) the stratified fine sandy gravel is seen 

 in open section extending down to the depth of 25 feet in the 

 old channel and resting upon probably reconstructed Oxford Clay. 

 Like the same gravels at No, 4 Pit, it contains erratics of con- 

 siderable size, so that they would both seem to be sub -glacial, 

 and to represent the ' ice-raft ' stage of the later glaciation of the 

 district. At both places they yield mammalian remains (including 

 SJ. primigenius), and have the same character in structure and 

 composition as that given above in detail for the No. 4 Pit. It is, 

 however, a noteworthy fact that at the latter place they overlap the 

 bank of the pre-glacial valley, with a deposit 8 or 9 feet thick, 

 indicating the widespread shallow-water conditions of the later 

 ice-raft stages of glaciation. That they are of later date than the 

 great Chalky Boulder-clay is evident from the fact that a ridge of 

 high ground some miles in length, to the south-east, consists of tliat 

 deposit, in which I recognized erratics from the Chalk, the Lias, and 

 the Carboniferous Limestone, when I visited it in company with 

 Mr. Abbott, to whose courteous guidance over the district I am much 

 indebted. 



VII. — The ' Weathering out ' of Striations upon Flint. 

 By J. Beid Moir, F.G.S. 



FOR some time past I have had a difficulty in understanding how 

 certain striated flints from various horizons stood, without 

 breaking, the pressure to which they must have been subjected 

 when such markings were imposed upon them. This difficulty 

 increased when I found that thin flakes from the present land surface 

 exhibited well-marked striae, and as experiments with my presses liad 

 shown that even large flints will break up under no very great 

 pressure, the possibility occurred to me of these scratches having 

 altered since the flints were first subjected to the scratching process. 

 I reasoned that if a point passed over a flint under pressure the 

 area upon which the point impinged would be shattered, and that 

 small plates or splinters of flint would be formed along the line 

 of movement. I also concluded that, as with the thin plates which 



^ A term used long ago by F. B. Jukes. 



