Reports and Proceedings—Geological Society of London. 1338 
Ha PORTS AND PROC rE DENG S. 
I.—Groroetcat Socrrry or Lonpon. 
January 12, 1910.—Professor W. J. Sollas, LL.D., Se.D., F.RB.S., 
President, in the Chair. 
The following communications were read :-— 
1. ‘On the Igneous and Associated Sedimentary Rocks of the 
Glensaul District (County Galway).’’ By Charles Irving Gardiner, 
M.A., F.G.S., and Professor Sidney Hugh Reynolds, M.A., F.G.S.; 
with a Paleontological Appendix by Frederick Richard Cowper Reed, 
M.A., F.G.S. 
The general succession of the rocks of the Glensaul district is as 
follows, in descending order :— 
3. ? Bata Beps. Conglomerates and Sandstones. 
These beds have not been studied. 
2. SHANGORT AND TouRMAKEADY Bens. Thickness 
(8) Calcareous gritty tuff of no great coarseness, sometimes becoming in feet. 
so calcareous as to pass into fairly pure limestone, enclosing 
also bands and patches of limestone breccia, and, more rarely, 
bands of highly fossiliferous limestone which in some cases 
has been shattered by earth-movements. 
(7) Very coarse tuff or breccia, mainly composed of felsite fragments : 
associated with it are impersistent bands of fine tuff . : 750 
(6) Tuff, coarse and fine, with occasional patches of calcareous beds, 
and at one point graptolitic beds indicating the zone of 
Didymograptus hirundo . : : i : 150 
(5) Great felsite sill of Tonaglanna and Greenaun . : about 1100 
(4) Coarse grit . : : ‘ : 20 
(3) Gritty tuff. : vary ing in thickness from 520 to 620 
(2) Coarse tuff or breccia, mainly composed of of felsite fragments. 75 
(1) Fine banded tuff . c : 5 : é 5 5d 
1. Mount Parrry Beps. . 
(4) Coarse grits . : 150 
(3) Fine arits and tuffs associated with black chert, a eraptolitie beds, 
and a prominent band of coarse tuff or breccia about 30 feet 
thick. The sree indicate the zone of Didymograptius 
extensus . : . : : . (?) 150 
(2) Coarse grits . : é ae ey 110 
(1) Coarse conglomerates, about 600 feet seen. 
The graptolitic beds occurring in Band 3 of the Mount Partry 
Beds have yielded nineteen species, which have been determined by 
Miss G. L. Elles, D.Sc., who considers that they indicate the upper 
part of the zone of Didymograptus extensus. The commonest species 
met with are D. extensus, Hall, and D. bifidus, Hall, both species 
being represented by small mutations. Rounded bodies, which 
a comparison with the better preserved specimens from the 
Tourmakeady district shows to be almost certainly Radiolaria, were 
noted in sections of the cherts and shaly beds at several points. 
In a previous description of the rocks of the Tourmakeady district, 
the term Shangort Beds was applied to a series of grits and tuffs, and 
the term Tourmakeady Beds to an associated series of calcareous 
strata which generally take the form of limestone breccias. In the 
