Geological Society. 283 



striking by the horizontal and discordant position of the true carbo- 

 niferous limestone of the neighbouring districts, was an important 

 addition to our information, and was heard with no small surprise 

 by many members of this Society. It gives us, however, a new 

 term of comparison with the phenomena of distant countries. The 

 greywacke' chain of Magdeburg contains innumerable impressions of 

 true coal plants, and some of the carboniferous deposits on the con- 

 fines of Westphalia partake (like the deposits in the South of Ireland) 

 of all the contortions of the older transition series. 



On the descriptions of the old red sandstone and the carboniferous 

 limestone I shall make no comments j but 1 think it right to recall your 

 attention to some valuable details respecting the metalliferous depo- 

 sits in the counties of Cork and Kerry. The copper ore of Ross 

 Island, on the lake of Killarney, does not constitute either metalli- 

 ferous beds or true veins, but is distributed in the form of branches 

 or strings, contemporaneous, like those of calcareous spar, with the 

 limestone rocks they traverse. At Mucruss mine, in the same neigh- 

 bourhood, copper ore was obtained from a true metalliferous bed. 

 In Kenmare the deposits of lead ore are shown to be discontinuous 

 masses, nearly parallel in range and dip to the regular strata. 



In the county of Cork the most valuable mine of copper is opened 

 in a true vein : . but the author remarks that in some parts of this 

 county there is a very general diffusion of cupreous matter, some- 

 times appearing in separate particles, and sometimes in strings, 

 veins or filaments more or h ss connected with each other, but not 

 continuous, and therefore contemporaneous with the rocks to which 

 they are subordinate. Such repositories of metals might not inaptly 

 be termed "veins of segregation," as they seem to have been formed 

 by a separation of parts during the gradual passage of the mineral 

 masses into a solid state. 



In England we have almost every variety of metalliferous deposits. 

 Near Whitehaven in Cumberland great masses of reniform hematite 

 alternate with red beds of mountain limestone. At Nosterfield, near 

 Bedale, a true bed charged with sulphuret of lead alternates with the 

 upper strata of magnesian limestone. The great copper pipe veins of 

 Ecton must have been contemporaneous with the shale limestone 

 to which they are subordinate. The great lead veins of our northern 

 counties originated, if I mistake not, in cracks formed during the ele- 

 vation of the carboniferous chain, before the period of the new red 

 sandstone. 



In Cornwall we have, as is well known, both on the great scale 

 and the small, every modification of veined structure. Tin is dis- 

 tributed through some of the granitoid rocks where no vein is visible. 

 The slate rocks, near their junction with the granite, are traversed by 

 veins of injection, and some of these are metalliferous, (for example, 



the slate series of Cumberland are so carbonaceous as to have given rise to 

 borings and other works in search of coal. I have been informed that 

 similar unsuccessful attempts were formerly made in North Devon. But in 

 none of these instances, I believe, were true coal beds and plants, like 

 those described by Mr. Weaver, ever discovered. 



2 O2 an 



