186 MESSES. KIRKBY AND DUFF ON THE 



south, to the extent of eighty fathoms or more, and four work- 

 able coals are brought in by it, as shown in figure 15. So far 

 as its course can be determined at the colliery named, it is 

 slightly to the north of east. It is connected with the Butter- 

 knowle fault by a cross fault of comparatively small magnitude, 

 called the Doghole "Dyke," which leaves the Wigglesworth 

 fault just to the east of Cockfield. At the latter place the Wig- 

 glesworth fault is scarcely more than a mile apart from the But- 

 terknowle fault ; between them runs the Cockfield Whin Dyke, 

 at first near the latter and almost parallel to it, but afterwards 

 bending away to the east-south-east. 



Another great fault evidently exists near to Brussleton Folly, 

 where the Measures rise sharp to the south, their inclination 

 being especially well seen on the Roman road near the top 

 of the hill, where the strata lie at an angle of 45°, as noticed at 

 p. 161. This dislocation may possibly be the Wigglesworth 

 fault continued to the east, as it is on a line with the assumed 

 course of the latter ; and it may be identical with a large fault 

 said to have been met with in West Auckland Colliery to the 

 south-west of the village. 



About two miles from Brussleton, in a south-east direction, 

 there is evidence of another dislocation, in an old sandstone 

 quarry close to Houghton-le-Side. The sandstone is yellow, 

 rather fine grained, thick bedded, with a dip to the north-west. 

 On the south side of the quarry, and apparently dipping beneath 

 the former rock, appears a quantity of dark grey limestone* 

 which passes beneath into a limestone shale, both of which con- 

 tain numerous Mountain Limestone fossils. These fossils have 

 kindly been examined and determined as follows by our friend 

 Mr. John Young, of Glasgow, well known as an authority on 

 Carboniferous species. 



Productus semireticulatus, var. Martha, Sow. 

 Spirifera lineata, Martin. 

 Athyris ambigua, Sow. 



* We were informed by a native that he had formerly quarried the limestone and burnt it 

 for lime, but with poor results, on account of its inferior quality. 



