420 



THE aEOLO&IST. 



OX TKE SKIDDAW SLATE VEINS. 

 By Peofessoe Harkjcess, F.R.S., F.G-.S. 



The author pointed out the several areas where the Skiddaw slates occur 

 in Cumberland and Westmoreland. He then proceeded to detail the na- 

 ture of a section from Newlands, between Derwentwater and Buttermere 

 on the south, to the carboniferous rocks at Sunderland on the north. This 

 section exhibits two well-marked axes ; and through the series of rocks 

 which occur between these axes and the green rocks appertaining to a 

 higher series, \\ herever the Skiddaw slates put on a flaggy character, these 

 strata afford fossils. 



A section from the green rocks on the north of Great Dod, across Sad- 

 dleback, the valley of the Caklen, and Caldbeck Fells, through the Skid- 

 daw slate beds, was next described. This section shows a considerable de- 

 velopment of metamorphic rocks in the valley of the Calden in connection 

 with the granite of Skiddaw Forest, as alluded to by Professor Sedgwick ; 

 and the strata in this section have for the most part a S.S.E. inclination. 

 In this section, where the rocks are not metamorphical, and when devoid 

 of cleavage, they also afford fossils. 



A section along the eastern margin of the Skiddaw slate and the super- 

 ficial green rocks of Westmoreland was next referred to. In this section 

 three small but separate patches of Skiddaw slates were pointed out, viz.. 

 one on the S.E. side of Ulls water, another in E-osgill Beck, and a third in 

 Thornship Beck ; and in the two latter Skiddaw slate has been worked for 

 slate-pencils. These also have furnished Professor Harkness with fossils, 

 and their appearance is the result of three ax;es occurring between Ulls- 

 water and Wastdale Crag. 



In a fourth section across Black Comb, the arrangement of the Skiddaw 

 slates, as these occur in their most southern position in the Lake district, 

 was also indicated. In the Black Comb area the prevalent dips are 

 N.JNT.W., and from near the base of the Skiddaw in this section fossils were 

 also obtained. 



The organic remains which Professor Harkness procured from the seve- 

 ral areas of Skiddaw slate consist for the. most part of graptolites. Of 

 these, there are two genera which have been recognized by Mr. Salter as 

 known in the Quebec beds of Sir W. Logan and in the Lower Silurians of 

 Australia, viz. Tetragrapsus and Dendrograpsus of Hall. Besides these 

 there is a phyllopod Crustacean, which Mr. Salter regards as identical 

 with a form from the Australian Lower Silurians. Professor Harkness 

 also indicated the occurrence of tracks in the Skiddaw slates, and pointed 

 out certain bodies which he regarded as the cases of Annelids allied to the 

 modern Terebella. 



The position of the Skiddaw slates and their fossil contents justify the 

 conclusion that they are referable to the horizon of the Lower Llandeilo. 



ON THE PALAEONTOLOGY OF MINEEAL VEINS, AND THE SECON- 

 DARY AGE OF SOME MINERAL 7EINS IN CARBONIFEROUS 

 LIMESTONE. 



By Chaeles Mooee, F.G.S. 



In directing the attention of the Geological Section of the British Asso- 

 ciation to the above subject, the author first referred to remarkable geolo- 



