Notices and Extracts from the Minutes of the Geological Society. 163 



the coal plants were on clay slate ; and all the impressions, which were nu- 

 merouSj were covered by beautiful white talc in very thin laminae. 



2. Notice accompanying Specimens of LeadOre, found in Toadstone, from near 

 Matlock, Derby shire. % Charles Stokes, Esq. f.r.s. &c. [Read Nov. 3,1820.] 



The specimens of Galena from the neighbourhood of Matlock, which ac- 

 company this notice, are from veins which have been worked with profit in 

 the toadstone as well as in the limestone. One of them is from the Side mine 

 under the High Tor, the other from the Seven Rakes mine, on the right 

 bank of the river not far from the bridge. 



The circumstance of the veins of lead being continued through the toad- 

 stone, although formerly denied, has been ascertained of late years in many 

 instances ; but it has rarely occurred that they have been worked in that rock. 

 This has arisen from the belief, commonly entertained and asserted by 

 most of the miners of Derbyshire, that the veins are productive only in the 

 limestone ; though it may perhaps appear on further examination, that this 

 opinion has been too hastily adopted ; and the circumstances of the working 

 of the toadstone in the Seven Rakes mine, show that this is probable, and 

 that some change has taken place in the opinions of the miners themselves on 

 the subject. 



This vein was formerly worked, to the depth of about thirty fathoms, in the 

 first limestone ; when, on coming to the toadstone, the work was abandoned, 

 as it was supposed that the vein was cut off by that bed. Some years after- 

 wards a level was driven into the hills, from near the river, to carry off the 

 water, and the vein was worked in the second limestone, underneath the toad- 

 stone, which was left untouched. The vein was again abandoned when the 

 workings were carried to a depth at which they could no longer be kept 

 clear from water : but about a year ago five working miners took a set of 

 the ground, in order to work the vein in the intermediate bed of toadstone 

 which had been left, and the undertaking has proved profitable. 



Mr. Tissington, the owner of the Side mine, who communicated to me 

 these circumstances, informs rae that the veins, in all the instances he is ac- 

 quainted with, are continued through the toadstone, although they frequently 

 do not bear well in that rock ; and also that a vein frequently changes its de- 

 gree of inclination in passing through it. And sometimes, after such a change 

 in inclination, the vein again returns at an abrupt angle, like a V placed 

 horizontally. 



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