220 BROWELL AND KIRKBY ON MAGNESIAN LIMESTONE 



ANALYSIS. 



Carbonate of lime 60 72 



magnesia 35-48 



Sand, clay, oxide of iron, &c 260 



Water 1-20 



100-00 



The per centage of carbonates of lime and magnesia in these 

 analysis of the Lower Limestone varies from 94-88 to 39-60 • 

 that of carbonate of magnesia 46 - 45 to 2*48. ISTo. 22 can scarcely 

 be called an analysis of this member, though it is that of a shale 

 belonging to the same period of deposition. 



We have already alluded to the economic uses of some of the 

 limestones of this formation. An excellent lime for building may 

 be obtained from most of the beds ; and some of them, from the 

 small quantity of carbonate of magnesia contained in them, would 

 evidently form a good tillage lime. Little can be said in favour 

 of these limestones as building stones, for as a rule they are thin- 

 bedded, difficult to work into suitable blocks, and unable to with- 

 stand the action of the weather. There is one exception to this 

 in a portion of the stone at Pallion Quarry, which is brownish 

 grey, concretionary, and five or six feet in thickness It with- 

 stands atmospheric action as well as any stone we have seen. 

 Several old houses are built of it in the neighbourhood of the 

 quarry, and it has recently been used with success in the new 

 church of St. Nicholas, at Sunderland. 



Sub-formation.— MIDDLE LIMESTONE. 



Geological Character. — Of various shades of yellow and brown ; 

 crystalline, compact, or friable ; of very irregular structure, and 

 generally unstratified ; usually fossiliferous. About one hundred 

 feet thick. 



No. 35. Locality— FTTL WELL RAILWAY-CUTTING. 



Lithological Characters. — Yellowish white limestone in the 

 state of fine powder — called marl by quarrymen. In this softer 



