PEOCEEDIXGS OP GEOLOGICAL SOCIETIES 



309 



about 45 fathoms still deeper. The entire basin is about 1500 feet in 

 thickness, with about 20 seams, containing about 28 feet of anthracite coal 

 " stone," or smokeless fuel, and about 123 beds of ironstone, varying from 

 1 to 4 inches of argillaceous iron-ore, averaging 30 per cent, of iron. 



{To be continued.) 



PROCEEDINGS OE GEOLOGICAL SOCIETIES. 



Geological Society of Londox. — JiDie 18, 1862. — 1. "On the Mode 

 of Formation of some of the River-valleys in the South of Ireland." By 

 Professor J. B. Jukes. 



Mr. Jukes's paper contained a description of the physical structure of 

 that part of the South of Ireland south of the limestone-plain that extends 

 from Dublin to Galway Bay. He showed that the Rivers Shannon, 

 Barrow, Nore, and Suir, after traversing this low ground, escaped to the 

 sea by ravines worn through lofty hills of Old Red Sandstone and Lower 

 Silurian rocks. He also instanced the rivers Blackwater, Lee, and Bandon 

 as each suddenly deserting the low longitudinal valleys through which they 

 had run for many miles, and turning at right angles down ravines of Old 

 Red Sandstone, notwithstanding the fact of the longitudinal valleys being 

 continued ith no apparent obstruction to the course of the rivers. He 

 showed the connection of these lateral ravines with the coming of strong 

 brooks from the higher ridges on the north into the longitudinal valleys, 

 and also that these brooks probably produced the ravines, having first 

 begun to erode them over a surface above the present ridges, and before 

 the formation of the longitudinal valleys. 



He considered the fact proved, that the present " form of the ground " 

 in the South of Ireland was produced by atmospheric erosion on dry land ; 

 and that the lim.estone ground was low because the rock had been dissolved 

 chemically as well as eroded mechanically ; and that its surface had sunk 

 to a lower level than the other rocks, like that of a glacier melting in its 

 bed. He proposed to extend this explanation generally to all dry land. 



2. "Experimental Researches on the Granites of Ireland. — Part III. 

 On the Granites of Donegal." By the Rev. Professor S. Haughton. 



The author described in detail the geographical position, physical struc- 

 ture, geological relations, and the chemical and mineralogical composition 

 of the granite of Donegal, which consists of four minerals — quartz, ortho- 

 clase, oligoclase, and black mica, with perhaps an unknown paste besides. 

 The oligoclase affords evidence of the probable identity of the granite of 

 Donegal with that of Northern Scotland and of Norway. The author also 

 alluded to his success in obtaining a formula for the determination of the 

 proportions of four minerals in a compound rock, from the relative specific 

 gravities of the mass and of its constituents. 



3. " On a Stalk-eyed Crustacean from the Coal-measures." By Pro- 

 fessor T. H. Huxley. 



This specimen, in an ironstone nodule, is crushed laterally, and exhibits 

 a side view of a Crustacean, similar in all essential respects to 'Pygocephalus. 

 The chief interest attaching to the specimen lies in the confirmation which 

 it affords of the author's interpretation of the specimens on which the 

 genus was founded. He draws the attention of collectors to the occurrence 

 of Crustaceans of such high rank in Carboniferous rocks. 



