and Marlborough Railways. 



169 



shews the cells to be from 10 to 15 diameters long with square ends, 

 abutting end to end and breaking joint. 1 



The occurrence of organic remains in Sarsen stone is extremely 

 rare. Some fragments of coniferous wood have been obtained, but 

 nothing to establish the connection of these blocks with either the 

 Woolwich and Beading beds, or the Bagshot sand, to both of which 

 their origin has been ascribed. It would therefore have been inter- 

 esting if the nature of the plant could have been deduced from the 

 microscopic structure, but Sir W. Hooker, Sir C. Bunbury, and 

 other distinguished botanists to whom specimens have been submit- 

 ted, are unable to say more than that they are of vegetable origin. 



At Little Bedwin I was fortunate enough to pick up two flint im- 

 plements. They were both lying on the surface of gravel which 

 had been moved in the construction of the Railway, and one has 

 all the characteristics of those of the post Pliocene period. It is of 

 spear head shape,5| inches long, 2j inches broad, and 1| inches thick. 

 In the other, advantage has been taken of a naturally formed slice 

 off the outside of a flint. It is oval, 3 inches long, and 1 \ broad, 

 and a sharp edge has been made by chipping the outer side of the 

 slice all round, the inner side being left just as it was before the 

 maker of the tool took it in hand. The difference in colour and 

 patina, between the natural fracture and the chips round the edge ; 

 and between the chips and a modern fracture, is very clear. 



Surface deposits were continually touched upon in the valley 

 between Little Bedwin and Crofton, but no good sections were 

 obtained, and in many places the construction of the Canal had 

 already interfered with the ground. At Crofton Engine, the valley 

 of denudation in which the rest of the course of the Railway lies 

 is entered upon. The upper end of this valley as far west as 

 Burbage is drained into the Kennet and the Thames through the 

 valley which the Railway has followed from Hungerford. On this 

 more will be said hereafter. In the cutting at Crofton Engine, the 

 chalk rock, that is the upper bed of the lower chalk, is passed 

 through, and from this to Woifhall bridge, the cuttings of the 

 Railway are in the lower chalk and chalk marl. 



1 Specimen and Sections are in the Museum of this Society. 



