TRANSACTIONS OF SECTION C. G99 



5. On the Raised Beeches of the Liffay Valley. 

 By G. H. KiNAHAN. 



FRIDAY, SEPTEMBER 4. 

 The following Papers and Report were read : — 



1 . 0)1 the Igneous Rocks of the Outer Blasket Islands. 

 By Professor J. Joly, F.R.S. 



2. The Laterite and Bauxite Zone, of North-East Ireland. 

 By Professor Grenville A. J. Cole, F.G.S. 



This paper was merely explanatory of an exhibit of the types of rock fornaed 

 during the interval between the basaltic eruptions in the north of Ireland in 

 Eocene times. It was urged, in agreement with the views of Richardson and Tate 

 and Holden, that the red lateritic zone represents basalt altered in situ even down 

 to depths of 40 feet, the so-called 'volcanic bombs' in the layer being residual 

 lumps of less altered basalt. Such a type of alteration is clearly connected with 

 the climatic conditions of Eocene times. Some of the pisolitic irnn-ore may have 

 accumulated on the surface of the laterite in pools formed during the rainy seasons. 

 The pale bauxites are derived from sporadic eruptions of rhyolite, and the 

 bi-pyramidal crystals of quartz in them prove this over a wide area. The thin 

 bauxitic layer, occurring as it does above the pisolitic iron-ore, may be in pare 

 formed by wind-borne material. 



3. The Igneous and Associated Sedimentary Rocks of the Tourmakeady 

 District, Co. Mayo. By C. I. Gardiner and Professor S. H. Reynolds. 



The oldest rocks are a series of grits, conglomerates, black slates, cherts, and 

 tuffs exposed along the eastern side of the area. The slates have yielded a large 

 series of graptolites, which indicate that the rocks are of Upper Arenig age. 

 Further to the west occur gritty tuffs and limestones, often of a peculiar brecciated 

 character, which have yielded a considerable series of fossils of Llandeilo type. 

 Quartz felsites, probably both intrusive and contemporaneous (rhyolites), play a 

 very prominent part throughout the district. 



4. The Lower Palmozoic Rocks around Killary Harbour, Co. Galivay, 

 and Co. Mayo. By E. G. Carruthers and H. B. Muff. 



The following succession was found in the Ordovician and Silurian rocks 

 around Killary Harbour : — 



1. Tetragraptus zone (Middle Arenig). — Black shales and cherts, 60 feet 

 thick, with Tetragraptus (four species), Dichograptas octobrachiatus, Didymo- 

 graplus e.vtensus, and other lorms, including two species of Diplograptus new to 

 the British Isles but known in North America. 



2. Diplograptus dentatus zone (Upper Arenig). 



(a) Leenane Grits, following conformably above the cherts on the south 

 shore of Killary Harbour. Conglomeratic grits with slate bauds 

 coming in towards the west in Rossroe, and a lenticular bed of 



