300 ME. A. STEAHAN ON THE PASSAGE OP A [Aug. I9OI, 



In a third boring, 300 yards from 'No. 2, but on the same level, 

 the same strata were proved, but no coal was found. 



The red colour of the rock in Ko. 1 boring is no doubt due to 

 staining by the New Eed Sandstone, which probably lies at no 

 great distance overhead, and in fact may have been touched in the 

 uppermost 2 feet of the bore-hole. Presumably it rests naturally, 

 though unconformably, upon the Coal-Measures, for some old pits 

 north of the colliery proved red rocks, some of which seem to 

 have been stained Middle Coal-Measures, while others are said 

 to have been JSTew Eed Sandstone. East of the colliery the New 

 Eed Sandstone is thrown in bj^ a fault. 



Explorations were then carried on to the north and south of the 

 main engine-slant (see fig. 2, p. 299). In the former direction 

 the coal has been worked for a distance of 980 yards, and in the 

 latter for 500 yards, so that the boundary of the barren area has 

 been proved for a distance of 1480 yards. The boundary runs 

 almost straight in a north-and-south direction, but at present there 

 is no further clue to the size or shape of the barren area. No 

 similar change has been seen in any of the seams, either in Flintshire 

 or South Lancashire. 



The stone, when first worked, is hard and black ; but after expo- 

 sure to the weather or washing with dilute acid much of it becomes 

 grey and displays various structures. The most conspicuous variety 

 is that described as consisting of small pellets. This is a pisolite 

 composed of spherules ranging from about jL to -J-|- inch in diameter 

 (E 3270^ : see PI. XII, fig. 1). The spherules are generally in contact 

 and mutually interfering, so that the mass presents a botryoidal or 

 mammillated appearance ; but sometimes they are isolated, and the 

 intervening spaces are filled with coaly matter. When cut across 

 they show a radiate crystalline structure, with less clear concentric 

 rings. Coaly matter occurs in them, and crystallization has obviously 

 taken place in water containing coaly matter in suspension. Thev 

 effervesce sluggishly with cold acid, and leave a somewhat copious 

 residue, consisting in part of crystals arranged in bunches or films 

 which have obviously formed part of the radiate structure, and in 

 part of brown or amber-coloured films of doubtful origin, but which 

 may be thin pellicles of coaly matter. The coaly matter between 

 the spherules also partly breaks down in acid, and leaves a residue 

 consisting chiefly of the brown filmy material with some crystalline 

 matter. In hot acid the crystals disappear with effervescence. 



An analysis of this rock by Dr. Pollard shews that it is a dolomite 

 of almost theoretically pure composition, with the addition of some 

 coaly matter, a little iron, and a not inconsiderable residue chiefly 

 made up of silica and alumina. The residue is no doubt clastic 

 material, and probably occurs in the spaces between the spherulites 

 as a coaly mud. The complete analysis is tabulated on p. 303. 



"^ The numbers in parentheses (E 3270, &c.) are those affixed to the slides in 

 the Geological Survey Collections at Jerinyn Street, London. 



