A.ND ASSOCIATED PERMIAN EOCKS OF DURHAM. 215 



ANALYSIS. 



Carbonate of lime 39 - 60 



magnesia . , 2824 



Oxide of iron and alumina 5-06 



Sand, clay, &c 24-06 



Water, &c. . . „ 1-28 



98-24 



No. 21. Locality— RYHOPE PIT. 



Litliological Characters. — Brown limestone, varying from a soft 

 earthy texture to a very compact one which fractures with sharp 

 cutting edges. From the basal beds of the Magnesian Limestone 

 at Ryhope, lying immediately above the Marl-slate. 



ANALYSIS. 



Carbonate of lime 57 - 12 



magnesia 31-36 



Oxide of iron, sand, clay, &c; 7'68 



"Water, &c 3-84 



100-00 



No. 22. Locality— RYHOPE PIT. 



Litliological Characters. — Fine-grained, grey, calcareous shale, 

 forming partings (from a quarter to one inch thick) between the 

 grey, compact strata, No. 19. Similar partings, but of a brown 

 colour, occur in other localities, in the same relative position. 



ANALYSIS. 



Carbonate of lime 4-20 



magnesia 2-60 



Silica, sand, and clay 75-93 



Oxide of iron and alumina 3-46 



Water, &c 10-79 



96-98 

 No. 23. Locality— RYHOPE PIT. 



Litliological Characters. — Yellow, compact, and marked with 

 dendrites. 



