140 PROCEEDINGS OE THE GEOLOGICAL SOCIETY. [June 1, 



soft sandstones and red marls, which attain a total thickness of 

 60 feet. The Magnesian Limestone, however, forms the thicker 

 portion. We found it divided into two principal beds ; the Yellow, 

 which was very hard and crystalline, 54 feet thick ; and the Blue 

 below it, containing bands of blue shale, 20 feet thick. Both to- 

 gether yielded 66 gallons of water a minute in our pits. 



Below the limestone we met with 33 feet of blue shale, which 

 made but little water ; and we then reached a very soft gritstone, 

 5 feet thick, which we consider the lowest bed of the Permian in 

 our pits. It is of the same character as a rock met with in a similar 

 position at Patricroft near Manchester ; and we have no doubt that 

 it is the equivalent of the " Quicksand," so well known in the 

 Durham district. 



Below the gritstone the Coal-measures begin with 5 feet of blue 

 shale, in which there are four bands of ironstone, and, immediately 

 below, a bed of the same stone, 15 inches thick, but of a richer and 

 apparently more regular character. 



The ore is principally in the state of peroxide, and the bed and 

 bands give an average of 42 per cent, of metallic iron, according to 

 the result of four analyses made in Dr. Percy's laboratory. The 

 following analysis, made by Mr. William Baker, shows the exact 

 composition and distribution of the constituents of the main bed : — 



100 parts, dried at 212° Fahr., gave 



Peroxide of iron 63 - l 10 



Lime 5-174 



Alumina 4-170 



Silica 6-545 



Sulphuric acid 0-293 



Phosphoric acid - 083 



Carbonic acid 9-702 



Water (in combination) 10-936 



100013 

 The above peroxide corresponds to 44-17per cent, of metallic iron. 

 The distribution of the constituents of the ore may be stated 

 thus : — 



Hydrated peroxide of iron 2(Fe 2 3 4-3HO) 61 -435 



Carbonate of protoxide of iron 15-293 



Carbonate of lime 8-869 



Sulphate of lime 0-629 



Hydrated silicate of alumina 12-650 



Phosphoric acid 0-083 



The lime present, being scattered through the stone in small 

 oolitic grains, gives the ore a very mottled appearance. As might 

 be expected, it is not affected by exposure to the atmosphere, though 

 very easily pulverized. At present it has only been proved in our 

 pits, which are 50 yards apart ; but Messrs. Dawes are now sinking 

 a pit, and will determine its regularity. It resembles the Froghall 

 ore of North Staffordshire, and a bed found at Patricroft in a similar 

 position as regards the limestone, more closely than any other iron- 

 stone of the Coal-measures. 



