GEOLOGY 



The Cannel Mine, which occurs some way above it, is remarkable in that it consists of a 

 basal layer of bituminous coal and an upper layer of cannel which has a thickness of 3 feet at 

 Wigan and thins away in all directions from it ; the common coal thickens as the cannel 

 diminishes. 



The coal itself has yielded numerous remains of fish-teeth, spines, scales, &c., as well as 

 large Stigmarian roots. 



The Trencherbone is of good quality in some parts of the area, whilst in others it contains so 

 much dirt as to prove unworkable. At Tyldesley it is associated with a bastard cannel. It is in 

 great demand as a house coal, and large quantities are sent into Manchester and other towns. The 

 Doe Mine and Rams Mine are also good and in great request. The Worsley Four-Feet, which 

 marks the upper limit of the Middle Measures, has been worked at Leigh, Pendleton, and other 

 places, and is a good coal. 



A great fault known as the Irwell Valley Fault cuts through this area from the Millstone 

 Grit, north of Bolton, in a south-east direction to Manchester, along the line of the valley of the 

 river Irwell ; the downthrow is to the north-east, and is over one thousand yards. The various 

 seams given on the section abut against the fault in regular order from north to south on the 

 upthrow side ; on the downthrow side the seams are shifted to the northwards, and a narrow tongue 

 of the Trias runs up into the middle of the coalfield. 



(C) WIGAN AND ST. HELENS AREA 



The St. Helens district forms the most westerly section of the South Lancashire Coalfield, that 

 of Wigan lying between it and the Bolton area. 



In this area, as in that previously mentioned, the Middle Coal Measures are about 1,000 yards 

 in thickness. 



Notwithstanding their nearness only two seams of St. Helens the Little Delf and Rushy 

 Park have been directly correlated with two of Wigan, viz. the Arley Mine and Smith Coal. 



The remaining seams are not equally capable of correlation owing to the changing character 

 of the coals themselves, to alterations in thickness and character of the intervening non-productive 

 measures, and to extensive faulting. 



ST. 



HELEN'S AND WIGAN 

 Wigan 



Measures 4 1 9 



Earthy Coal (with partings) ... 62 

 Measures with Coal, 2ft. . . . 121 6 



Coal-seam of Red Rock Brow 



Riding Mine 



Measures 



Ince Yard Mine .... 



Measures 



Ince 4~feet Mine .... 

 Measures with 3 coal-seams. 



Ince 7-feet Mine .... 



Measures 



(Wilcock or( Coal 2 ft. 1 1 in. 

 \ Furnace \ Clay o ft. 6 in. 

 ( Coal ( Coal I ft. 8 in. 



Ft. 



4 



36 



2 



108 



3 

 150 



6 

 7 1 



252 



3 



2 



45 



387 

 5 



90 

 4 



72 



1 ' Geology of the Country around Wigan,' Mem. Gcol. Survey, by Prof. E. Hull (i 



5z), p. 12. 



