234 A POPULAR SKETCH OF THE 



Hungher Hill Mines, near Snitterlon. 



1st Limestone 21 feet. 



1st Toadstone 84 



/-Limestone 72ft. Oin. 



1 Three clays 6 

 2nd Limestone < Limestone 36 



iciay 2 



V-Limestone 12 3 120 



2nd Toadstone reached, hut not pierced through.* 



To these proofs may be added, the toadstone beds seen in Lath- 

 kill Dale and at Fin Copt Hill, and left uncertain by Mr. Hopkins, 

 and probably, also, the beds seen in the High Tor and at Masson 

 Lowe, near Matlock. When, however, we come to the question of 

 the thickness of these different portions of the limestone, we again 

 seem environed by difficulties. At Ashover, the whole distance 

 between the bottom of the shale and the top of the toadstone, as 

 seen in the shafts of the Gregory mine, is not more than 180 feet ; 

 and in Matlock High Tor and other points of the eastern boundary 

 of the limestone district, where the whole thickness of the first lime- 

 stone must be visible, it does not seem to be much more. At Tides- 

 well Moor, however, Mr. Hopkins mentions a sinking in the first 

 limestone of 600 feet without reaching the toadstone, and estimates 

 the depth of the toadstone at a similar rate in the district around 

 Monyash and north of Middleton Moor, by Wirksworth, and other 

 places. Even, therefore, if we suppose with him, (and which pro- 

 bably is the case) that the first toadstone of the east part of the dis- 

 trict thins out towards the west, and its place is occupied by lime- 

 stone, there still seems a great irregularity in the thickness of the 

 upper part of the limestone formation, in different parts of the 

 district. Of the thicknesst of the lower part of the mountain lime- 



* My friend, Mr. Alsop, of Darley Dale, informs me that, a few yards 

 further on, this second bed has been sunk through, and its thickness ascer. 

 tained to be 108 feet. 



•f If, in the south east part of the district, we estimate the beds as follows; 



1st Limestone 200 feet 



1st Toadstone 90 



2nd Limestone 120 



410 



we shall get 410 feet as the extreme thickness which the first limestone 

 ought to have over that part of the district where there is only one toad- 



