PROCEEDINGS OF 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.) 
PEOCEEDINGS OF GEOLOGICAL SOCIETIES. 
Geological Society of Londox. — June 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, 
Barrovr, ]S'ore, 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 with 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 b}^ atmospheric erosion on dry land ; 
and that the limestone ground was low because the rock had been dissolved 
chemically as well as eroded mechrinically ; and that its surface had suuk 
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 Bev. 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 jN'orthern Scotland and of Is orway. 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 Pygoceplialus. 
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. 
