264 



THE GEOLOGIST. 



In the middle series there are a large number of seams, and the field is 

 divided into many divisions by main faults — the largest extending to a 

 thousand yards of vertical displacement or throw. 



The part known as the Burnley coal-field is not a detached portion, as 

 is sometimes supposed and laid down on maps, but is connected with the 

 main field by the lower strata up to the Grannister coal. The southern 

 boundary, of what may still for convenience be termed the Burnley coal- 

 field, is a remarkable fault, which runs nearly due east and west instead of 

 north-west, like nearly all the other principal faults. At the eastern end this 

 fault crosses the valley between Calder Head and Holme ; it then passes 

 Thieveley, where it has been worked for lead ore ; then on to Burnt Hills, 

 near Clawe Bridge, where lead ore has also been found in it, and also at 

 Cupola, a name derived from the furnace formerly used for smelting the 

 ore which was then worked. The fault then continues'westwards through 

 the town of Church to the south of Bishton. For the most part of its 

 course it consists of two faults, which are sometimes near together and 

 sometimes run from 500 to 700 yards apart. The northern one is a down- 

 throw to the south of about 70 yards, and the southern one a downthrow 

 to the north of about 250 yards, forming a trough or deep belt between. 

 The two faults taken together may be looked upon as a great anticlinal 

 division. The strata on the south side dip for the most part at a slight 

 angle southwards into the main coal-field ; and on the north side they dip 

 to the north, forming the Burnley coal-field. 



The contour of the Burnley coal-field forms nearly half a basin. The 

 north- western outcrop is very steep, the dip being nearly at an angle of 

 45°, and is called the "rearers." Like other parts of the Lancashire coal- 

 field, the Burnley basin is divided by large faults, most of which have a 

 direction 35° west of true north. By these faults it is divided into six se- 

 parate main divisions, in each of which the Arley four-feet coal has been 

 found near the centre. 



In the Altham basin, the Hapton basin, and in the Habergham basin, 

 the Arley mine is worked. 



In the fifth, or Burnley basin of the Burnley coal-field, the Arley mine 

 extends over a large area. It is there where the greatest depth of strata 

 in the Burnley basin are found. 



Sixth, and last, is the Marsden basin, where the Arley mine is also 

 worked. This basin extends to near Colne, where the mountain four-feet 

 is now being worked. The bedding of the strata in these six divisions of 

 the Burnley coal-field is more laminated, or flaggy, than at most other 

 parts of the Lancashire coal-field. 



At Clayton and Bradford, on the east side of the city of Manchester, the 

 coal strata are apparently surrounded by " red rock." which disconnects 

 the upper coal-seams from those at Pendleton and other places. 



At Patri croft, and Bedford, near Leigh, thin limestones are also met 

 with ; but they are not stratified with the coal-measures, and are classed 

 with "red-rock " (Permian) strata, which here overlie the coal-measures. 



The paper is illustrated by a remarkably fine seciion of the beds, more 

 than 6 feet in length, giving the name and thickness of every stratum and 

 seam. 



Another paper was read " On some horses' teeth, and a supposed worked 

 flint found in the drift at Barrowford. near Burnley." by Mr. J. Whitaker. 

 In the wider parts of the valley the Boulder clay is covered by three or 

 f>ur yards of gravel, on the top of which lies sand about two feet thick, 

 covered by three feet of fine sandy soil, the whole resting on the millstone- 

 grit series of rocks. The teeth were found during the cutting of a trench 



