1821.] Geological Society, .. 67^^ 



^ ■ ' GEOLOGICAL SOCIETY. '^ *'^ ^i'?r? 



The meetings of this Society were resumed on Nov. 3, wnea 

 the following papers were read : 



A notice accompanying specimens of Lead Ore in Toadstone, , 

 from near Matlock, Derbyshire, by Charles Stokes, Esq. MGS, [ 

 was read. 



It has been a prevalent opinion that the veins of lead ore , 

 which occur in the hmestone of Derbyshire do not traverse the 

 beds of toadstone which alternate with the limestone. It appears, 

 however, from the information of Mr. Tissington, that this is aa 

 error. A vein had been worked in the hmestone above the. 

 toadstone at the Seven Rakes mine, and abandoned on coming 

 to toadstone from the general idea that the veins were cut off by , 

 it. About a year ago, however, some miners ascertained that, 

 the vein continues through the toadstone, and it is now working , 

 with profit. Another' vein in the side mine is also working in 

 the toadstone. 



A notice of fossil plants having been found at the Col de 

 Balme, by H. T. de la Beche, Esq. MGS. was read. 



The Col de Balme at the head of the valley of Chamouny, . 

 -which by M. Ebel is stated to consist of primitive rocks, is com-! 

 posed of beds of clay-slate, of limestone, and of a few thin beds 

 of sandstone : these seem to be a continuation of the limestones 

 which are remarked in patches in the valley of Chamouny, and ^ 

 which probably once occupied the whole length of the valley. 



While crossing the Col de Balme in the autumn of 1819, 

 M. de la Beche collected specimens of the thin beds of sand- 

 stone containing vegetable impressions precisely similar to those . 

 which are usually found in coal formations. He also procured . 

 at Chamouny some specimens of clay slate found on the Col de^ 

 Balme, and which had impressions of the plants of coal forma- 

 tions covered by beautiful white talc in very thin laminae. 



The " Supplementary Remarks on Quartz Rock,'' by Dr. 

 Macculloch, MGS. were read. 



A further examination of the westward of Sunderland, where 

 gneiss abounds in all its varieties from the granite to the schis- 

 tose, has enabled Dr. Macculloch to ascertain its alternations 

 with. quartz rock. The latter appears sometimes in a detached^ 

 state, occupying the summits of those mountains of which the^ 

 chief mass consists of gneiss, as is the case in Ben Stack, and 

 in the northernmost Ben More ; or it is found covering extensive 

 tracts of country, and occupying the lowest as well as the 

 nighest land, as in the instance of the great tract from Ben More 

 Assynt to Canasp and Curiach. , 



On the north side of Glendhu, the bed of quartz rock is about 

 100 feet thick: it reposes on the gneiss which extends to' the, 

 western sea, and consists of very even and parallel strata, of an' 

 extremely compact variety. This mass is followed by a similar 



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