22 Mr. N. J. Winch on the Geology of 



of its direction a vein is found traversing Walker colliery, and 

 crossing the Tyne at Walker near Mr. Reay's house. In the latter 

 colliery it has heen observed and described by Mr. George Hill, to 

 whose accuracy I owe the plan given in Plate 3, and the following 

 particulars. 



The dyke is well defined, and the Plate represents its horizontal 

 section taken at the level of the high main coal 300 fathoms from 

 the surface. It occasions no alteration in the level of the coal- 

 measures, and the depth to which it intersects them is unknown. 

 The dyke has been cut through by horizontal drifts in four places, 

 from which the following sections have been taken. 



Sections at A. A. the two western drifts. 



1. Coak 6 



2. Hard greenish whinstone, firm and unbroken 3 



3. A fissure filled with nodules of whinstone and post imbedded 



in a cement of blue slate Q 



4. Loose fragments of whinstone and post imbedded in blue slate 



but commonly less deranged 323 



5. Hard greenish whinstone similar to No. 2 6 



6. Coak 3 1 G 



Yards 22 1 6 

 Sections at B. B. the two eastern drifts. 



1. Coak very hard 1 



2. A confused mixture of nodules of sandstone, whinstone, pyrites "S 



and calcareous spar (the sandstone predominating) cemented/ 



together by pieces of blue and black slate. Water was found, > 6 



and there was a plentiful discharge of inflammable gas, while V 

 the drift was being made J 



3. Compact post, with pieces of black argillaceous slate occurring 



at intervals 316 



4. Hard greenish whinstone 8 16 



5. Coak like that of No. 1 1 



Yards 20 . 



