OP THE COUNTY OF LEICESTER. 9 



The junction of the two formations is quite abrupt, without any 

 oradation of one into the other, and the position of the new red 

 sandstone is, as before stated, always unconformable to that of the 

 coal measures. They consist of many beds of coal, alternating with 

 shales and sandstones, of which the shales greatly predominate ; good 

 beds of ironstone also occur, but are not now worked. For details 

 of the sinkings, the number and thickness of the several beds, as 

 well as for figures of all the characteristic fossils of the Ashby coal 

 field, I must refer the reader to the late Mr. Mammatt's elaborate 

 work upon that district, confining myself here to a mere outline. 

 The Ashby coal field may be divided into three distinct districts, or 

 basins, as they may be termed :— 1. That of Measham on the south 

 west, which is now little worked, being almost exhausted ; 2. North 

 of the Measham basin lies that of Moira, containing the collieries of 

 Moira, Gresley, Swadlincote, Stanton, and Newall ; 3. East of 

 both these lies what may be called the Swanington basin, including 

 the collieries of Lount, Pegg's Green, Coleorton, Whitwick, Snib- 

 ston, Heather, Ibstock, and Bagworth. The boundaries of these 

 basins are, however, irregular and ill defined, their edges being much 

 covered up and obscured by unconformable beds of the new red 

 sandstone. 



Of the Measham basin little or no information is now to be ob- 

 tained. The Moira basin occupies a district about five miles in dia- 

 meter, the Moira colliery being the deepest and most centrical. The 

 main coal at Moira is thirteen feet thick, consisting of two beds, of 

 which the uppermost has a thickness of seven feet, and, being there 

 the best, is the only part worked. Proceeding north west from 

 Moira, however, these beds become separated by a parting of shale, 

 which increases from eighteen inches, at Swadlincote, to twenty 

 yards, which is its thickness at Newall ; and over this district the 

 lower coal is the best and most worked. At Stanton, however, one 

 mile west of Newall, the parting being eighteen yards thick, the 

 upper bed regains its quality, and is the one worked in that colliery. 

 The Moira basin is much broken by faults,* the principal of which 

 run twenty or thirty degrees west of north, and are crossed by others 

 at right angles to them. One of the largest of the north west faults 

 runs in a directly straight line from Brambro, through Moira colliery, 

 Swadlincote, and Spring Wood, to near the Decoy in Bretley Park, 



• A fault is a fracture of the strata, causing an elevation or depression of 

 the beds on one side of it from their original level. 



VOL. VIII., NO. XXIII. * 



