48 
BARIUM SULPHATE. 
BARIUM SULPHATE AS A CEMENTING MATERIAL 
IN SANDSTONE.* 
•BY FRANK CLOWES, D.SC. 
Biscliof mentions instances of foreign sandstones in 
which the material cementing the sand grains together is 
barium sulphate, but it appears that up to the present 
time no such sandstone has been met with in the United 
Kingdom. Having learned from my colleague, Professor 
Blake, that opinions differed regarding the calcareous nature 
of certain New Red Sandstone beds in the neighbourhood 
of Nottingham, I undertook to examine the chemical com¬ 
position of these sandstones. 
At the spot in question the sandstone appears as two 
hills, known as Stapleford and Bramcote Hills, and in the 
intervening valley there is a pillar of rock called the Hem¬ 
lock Stone. The hills are conical in shape ; the Hemlock 
Stone is a mushroom-shaped pillar some twenty feet in 
height. Professor Blake visited the spot with me some 
short time since, and we procured specimens of the sandstone 
from different levels of the hills, and of the Hemlock Stone. 
One of these portions was placed in the hands of two senior 
students for careful analysis, with the result that the sand¬ 
stone was reported to contain about thirty per cent, of 
barium sulphate. I have recently found that the whole 
of the sandstone specimens from the two hills already 
mentioned contain this sulphate in varying proportions, 
which are at present being determined with care, whilst 
some of the lower beds also contain calcium carbonate. 
Those geologists who collected their specimens from the 
lower portions of the Hemlock Stone would undoubtedly 
detect a carbonate by the ordinary test with an acid, and 
would therefore consider the sandstone to be calcareous ; 
but if they had procured samples of the mushroom-shaped 
top of the stone they would have found no carbonate, 
and would have failed to detect by the acid test the true 
* A Paper read before Section B, British Association, Aberdeen 
Meeting. 
