234 THE CARBONIFEROUS SYSTEM. 



including angular fragments of the shale, some beds of which on this 

 side are very tender and cleave readily into rhomboidal pieces. The 

 coal enveloping these fragments must have been softened sufficiently 

 to allow them to penetrate it, but it has more numerous and less 

 regular divisional planes than in the central parts of the mass, and 

 has probably been shifted or crushed somewhat, either when it re- 

 ceived the included fragments or subsequently. Both at the roof 

 and floor, the coal shows distinct evidence of a former pasty or fluid 

 condition, in having injected a pure coaly substance into the most 



minute fissures of the containing rocks. 

 Fisr. 65. — Relation of the '■'■Albert ,-,1,1 c j n i \ 1. 



%,„,,, , . . , , On both roof and floor also, but espe- 



Coal to the contmning beds, as ' '■ 



seen near the shaft of the viine. cially the latter, there are abundant 



evidences of shifting and disturbances in 

 the slickenside surfaces with which they 

 abound. All these appearances I have 

 endeavoured to represent in Fig. 65, 

 which agrees in the essential points with 

 a similar figure given by Professor 

 Taylor, who does not, however, repre- 

 sent the contorted state of the beds and the crushing of the lower side 

 of the coal. 



" The levels of the mine extend on both sides of the shaft along the 

 course of the coal. On the south-west they extend about 170 feet, 

 when the coal narrows to a thickness of one foot. In this direction, 

 however, I had not time to examine them. In proceeding to the 

 N.E., the coal has a general course of N. 50° E., bending gradually to 

 N. 65° E., and everywhere presenting the appearances already noticed, 

 though attaining, in one place, a width of thirteen feet. At the distance 

 of about 200 feet from the shaft, a remarkable disturbance occurs. 

 The main body of the coal bends suddenly to the northward, its course 

 becoming N. 29° E.* for about twenty-five feet, when it returns to a 

 course of N. 50° E. At the bend to the northward, a small part of 

 the vein proceeds iu its original course, and is stated by the persons 

 connected with the mine to run out, leaving a large irregular promon- 

 tory of rock between it and the main body of the coal. This disturbance 

 has been variously represented as a fault, and as a cutting of the vein 

 across the strata. Though I confess that the appearances are of a 

 puzzling character, and are but imperfectly exposed in the mine, the 

 impression left on my mind is, that it is, on a large scale, a flexure 



* These measurements were made with a pocket prismatic compass. They differ 

 slightly from those of Dr Jackson, either from accidental circumstances, or from being 

 taken in different levels of the mine. 



