By Wm. Gunnington, F.G.S., & Wm. A. Cunnington, Ph.D. 133 



of it may be found adhering to the surface of the flints, and even 

 to the surfaces which have been worked by man. In certain 

 instances, where a stone appears to have split during working, the 

 dioxide has penetrated into the cracks and effectively recemented 

 it. 1 We have also observed deposits of manganese dioxide on the 

 sarsen fragments found in the gravel at Knowle. 



We have yet to refer to the secondary deposits of silica which 

 are not infrequently found on the surface of the flints. It is not 

 easy to understand what were the chemical and physical conditions 

 which prevailed when these deposits took place, but there can be 

 no doubt as to their frequent occurrence. The silica is generally 

 of the chalcedonic variety, occasionally assuming a fibrous structure, 

 —moss-like or in small rods. Such deposits of silica do not usually 

 present a polished surface. The layers are generally very thin, 

 and are frequently much worn down, sometimes only a mere film 

 remaining. Very distinct patches of the botryoidal form may 

 occasionally be found even on the worked surfaces of implements 

 from this, as well as from other localities, though the fact appears 

 to have been very generally overlooked. Some well-defined im- 

 plements closely covered with scratches, appear to have received a 

 thick deposit of white silica which has filled up the scratches. 

 They have since been abraded to a smooth surface, much of the 

 deposit having been removed, so that the dark colour of the original 

 flint shows through on the prominent ridges. 



The implements are very varied in form, and in the style of 

 working; some, especially those of the ovate pointed type, are 

 cleverly flaked, in this respect resembling neoliths. Others are 

 exceedingly rude, almost shapeless, and difficult to recognise as 

 having been wrought by man. In many, even of very rude type, 

 it is nevertheless evident that care has been taken to form a good 

 point to the tool, and to secure such a wedge-shaped form as would 

 render it suitable for fixing in a handle. 



1 Several examples of this phenomenon occur in the Knowle gravels. It 

 is particularly well shown, however, in a large flint core, from Galley Hill, 

 Kent, now, by the liberality of Mr. T. H. Powell, in the North Wilts Museum 

 at Devizes. 



