﻿1851.] ORMEROD ASTLEY MAGNESIAN LIMESTONE. 269 



6 feet in thickness. These are overlaid hy 1 5 feet of clay and surface- 

 soil, making the total depth of the shaft 126 yards. Mr. Darlington 

 states that the amount and direction of dip at the shaft are the same 

 in the Coal-measures and the Permian beds, being about 10° S.S.E. 

 This pit is the most easterly point at which the Magnesian Limestone 

 has been found in this district. At the place where the bore-holes 

 were made the beds are not exposed to view, so that the dip at that 

 place cannot be given. The surface of the land at the central bore- 

 hole "B," is about 3 feet below the natural surface at the pit-mouth. 

 The borings at "B" show surface-soil and clay 17 feet 5 inches, and 

 Magnesian beds 10 feet, showing an increase of thickness over that 

 at the pit. 



In the most northerly boring, " A," there are five beds of limestone, 

 varying in thickness from 1 inch to 3f inches, and amounting to 11^ 

 inches. The intervening beds of Red-earth vary from J of an inch 

 to 5^ inches and amount to 8^ inches, making the thickness of the 

 Permian beds, without including the Red-earth under the lowest 

 limestone, 1 foot 7 J inches. The total depth of this boring is 21 feet 

 8^ inches. 



In the central boring, " B," there are twenty-eight beds of lime- 

 stone, varying in thickness from 1 inch to 8J inches, and amounting 

 to 5 feet 6f inches. The intervening beds of Red-earth vary from 

 J of an inch to 6f inches, and amount to 4 feet 6 inches, making the 

 thickness of the Permian beds, without including the Red-earth under 

 the lowest limestone, 10 feet f inch. The total depth of this boring 

 is 28 feet 8-£ inches. 



In the most southerly boring, cf C," there are twenty-five beds of 

 limestone, varying in thickness from \ an inch to 8f- inches, and 

 amounting to 5 feet 6 inches. The intervening beds of Red-earth 

 vary from \ inch to \\ inches, and amount to 4 feet \ inch, making 

 the thickness of the Permian beds, without including the Red-earth 

 under the lowest limestone, 9 feet 6 \ inches. The total depth of this 

 boring is 69 feet 8 inches. 



The average thickness of the beds of limestone is 2\ inches, and 

 that of the intervening Red beds 2 inches. 



Mr. Darlington informs me that on the deep of his workings the 

 Magnesian Limestone is covered by the Red Sandstone, having the 

 same dip as the Magnesian Limestone. 



The following is an analysis of the unburnt limestone and inter- 

 vening beds at the borings above mentioned : — 



Insoluble in Acids 



Soluble Silica 



Sesquioxide of Iron 



Alumina 



Carbonate of Lime 



Carbonate of Magnesia... 



Soda 



Loss 



Clay Beds. 

 68-0 



Limestone Beds. 

 16-6 



0- 33 

 7-0 



1- 33 

 18-0 



5-0 

 0-34 



Soda & Potash 0-66 

 0-69 



10 



4-66 

 2-66 

 63-4 

 10-33 



32-0 



83-4 



100-0 



100-0 



