of Korthumlerland and Durham. 83 



deavour to give a brief account from my own observations. It 

 may be proper to remark previously, that the strata in these 

 counties are frequently broken and deranged by numerous nearly 

 perpendicular wal!-". or dvkes both of clay and whin-stone (basalt) 

 of vast extent; besides which, numerous blocks of whin-stone, of 

 a different kind from any which these dykes furnish, art scat- 

 tered over the surface of the country. 



The calcareous strata and magnesian lime, which for the sake 

 of conciseness I will denominate the Sunderland limestone, (be- 

 ing there most extensively quarried,) is lost on the south-east 

 under the alluvial ground of the river Tees, and cut off in that 

 direction by the lofty range of the Cleveland Hills: but the same 

 formation makes its appearance on the south-western side of these 

 hills, and is continued through Yorkshire into Nottinghamshire 

 and Derbyshire and through the south-eastern counties. The 

 chalk and roestone, which are the upper series of these strata in 

 other situations, are stripped off, if they have ever covered the 

 magnesian limestone of Northumberland and Durham. 



The Sunderland limestone formation extends along the coast 

 north of the TjTie, but not in a continued line. The whole thick- 

 ness of this limestone has not been measured ; nor would it be 

 easy to acertain it, as some of the rocks are very indistinctly 

 stratified. I think it cannot be less than one hundred and fifty 

 yards. Two hills on the west of Sunderland, containing nu- 

 merous marine organic remains, I am inclined to consider as of 

 subsequent formation. 



On the banks of the Wear, about two miles west of the Iron 

 Bridge, the lower beds of the Sunderland limestone are very ex- 

 tensively quarried to the depth of at least one hundred and thirty 

 feet from the surface : it is here most distinctly stratified, rising 

 in large tables and slabs well suited for building stone, being 

 compact and extremely durable. In one instance, and in one 

 oidy that I could hear of, have any organic remains been found 

 in the limestone of this quarry. The perfect impression of the 

 head and vertebrae of a flat fish about seven inches in length, was 

 discovered in dividing a slab of this stone : one side of the im- 

 pression was presented to the Sunderland Museum ; the other 

 is in the possession of J. Gootlchild, Esq. the proprietor of the 

 quarry. I am more inclined to believe that the rare occurrepce 

 of organic remains in these rocks is to be attributed to some 

 process of nature by which they have been obliterated, than to 

 conclude that they never were imbedded in them. 



Near the quarry I have just mentioned, an attempt was lately 

 made by Mr. Goodchild to search for coal by boring through 

 the limestone. It was attended with much expense, but with 



F 2 complete 



