114 



CORNBROOK COAL-FIELD. 



and beneath the Four -feet coal is a hard white sandstone, with red and grey shale. The 

 lowest coal seams repose on the conglomerate and sandstone representing the millstone 

 grit. Such is the general arrangement of the strata, where they are fully developed. 

 The largest and most productive portion of this coal tract, called Cornbrook, is, as before 

 stated, entirely covered by basalt, and the coal is there uniformly worked by shafts sunk 

 through that rock, which varies in thickness from twenty to sixty-four yards. In these 

 works the proprietor, Mr. Botfield, has hitherto confined his operations to the three 

 principal seams above mentioned. The following is a section of the beds passed through 



in one of his shafts : 



Yds. Ft. In. 



Basalt, or "Jewstone" 50 1 6 



Rotten Jewstones, and brown clunch 3 0 0 



Blue bind or shale 3 q q 



Red rock 4 0 0 



Pinney stone roof (ironstone) 2 0 0 



Pinney stone measures (ironstone) 3 0 0 



Horse-flesh earth (hard clunch of reddish colours) 3 0 0 



Rock and bind mingled together 10 0 0 



Blue bind 2 0 0 



Chance rock 8 0 0 



Rock and bind mingled together 12 0 0 



Blue clunch 4 1 6 



Great Coal rock (sandstone) 9 0 0 



Great Coal roof (shale, &c.) 2 0 0 



Great Coal 2 0 0 



Great Coal poundstone 2 0 0 



Bottom rock 116 



Clumper , 2 16 



Smith Coal 1 \ q 



From the Smith Coal to the Four-feet Coal, 3 yards ... 3 0 0 



Four-feet Coal 110 



4 10 



129 2 6 



The Knowlbury basin being free from the cover of basalt is more clearly exhibited 

 than that of Cornbrook. (See PL 30. fig. 7.) Its form is elliptical ; the major axis 

 being about a mile in length. On the south and west, it is flanked by the Old Red 

 Sandstone; on the north and north-west, by an elevated line of works in the lower 

 coals, called the Gutter ; on the north-east, by an escarpment of basalt and the Treen 

 pits (the south-eastern face of the field of Cornbrook) ; and on the east by the millstone 

 grit and a band of carboniferous limestone. The inclination of the strata upon the 

 opposite sides of the basin is variable. On the west, the lower beds of coal and sand- 

 stone crop out at angles of about 30°, resting on the Old Red Sandstone. At the 

 south-western extremity an adit being driven from the lower country of Old Red Sand- 

 stone into the heart of the coal works, the exterior or lower carboniferous strata were 

 found in much more highly inclined positions (60° to 70°) j but the angle decreased as 



