126 History of the Sarsens. 
In the gravels and brick-earths of Surrey, Berks, and Wilts 
water-worn Sarsens and more or less rounded fragments are of fre- 
quent occurrence. Some of the more usual sizes are :— 
Length. Breadth. Thickness. 
Inches. Inches. Inches. 
23 19 15 
23 24 7 
17 8 10 
IIJ.—ConstituTion OF THE SARSENS. 
In their composition the Sarsens are sandy,—in fact they consist 
of quartz sand, either fine or coarse (grit), sometimes with pebbles 
and angular bits of flint in greater or less quantities. As to their 
structure, their internal appearance very roughly resembles, in most 
cases, that of broken loaf-sugar ; hence it is said to be “ saccharoid ” 
or “saccharoidal”; sometimes they are more closely crystalline. 
In the middle they are dense and hard, the sand-grains being close- 
set and strongly cemented with silica (the same natural substance 
as the quartz and flint). The sand has been derived from very old 
rocks containing or made of quartz; such as granite, quartzites, and 
quartz-veins in schists. The first-named is the most likely source ; 
and, while the quartz-grains remained, after its degradation, to form 
sand-beds, and the mica was floated away to a distance, the de- 
composed felspar yielded the kaolin to form the clay-beds associated 
with the sands of the Tertiary formations, and free silica also 
sufficient in some instances to cement the sands into blocks, if not 
as whole beds. The flint pebbles have been derived from the Chalk. 
On their surfaces they are often soft and friable: the sand-grains 
either not having been closely cemented, or having lost their holding 
power. The sand itself is white and pellucid, or colourless ; but it 
is stained! very generally with iron-oxide or natural iron-rust. 
Hence the stones very often have an irony, rusty, or ferruginous 
colour of more or less intensity; and the outer part is frequently 
1 Noted also by Mr. W. Cunnington, as quoted by Mr. W. Long, Wilts Mag., 
vol. x., pp. 71—74. 
