130 Geological Society : — 



' stratified traps.' There were also areas here, especially to the 

 south, where escape was impossible and domes were formed. 



The author observes that his conclusions, if correct, may be 

 applied to explain the source of the Deccan trap without eruptive 

 centres. It may have been forced out from innumerable orifices as 

 from a sieve, none of these being so much larger than others as to 

 make a definite centre. 



June 9th. — Dr. Henry Hicks, E.R.S., President, 

 in the Chair. 



The following communications were read : — 

 - 1. ' The Cretaceous Strata of County Antrim.' By W. Fraser 

 Hume, D.Sc, F.G.S. 



The paper, which deals with the Irish Cretaceous strata, is 

 divided into four parts. 



I. This contains a detailed account of the principal subdivisions, 

 their local distribution, and characteristic fossils. The area occupied 

 by these rocks is separated into five divisions, each marked by 

 special lithological and palaeontological features. These are : — 

 (a) The Southern Division, extending from Moira to Lisburn. 

 Here the highest zone of the Chalk, that of Belemnitella mncronata, 

 rests directly on theTriassic strata, the junction-bed containing large 

 pebbles, associated with the above-mentioned species. — (b) The 

 Central Division, mainly including the sections between Lisburn 

 and Belfast. All the main lithological features are here displayed, 

 namely : 1 . Glauconitic Sands (a blue-green rock rich in glauconite) ; 

 2. Glauconitic Marls ; 3. Yellow Sandstones (a light calcareous sand- 

 stone) ; 4. Chloritic Sands and Sandstones of the Exogyra columba- 

 zone (yellow-green sands and sandstones) ; and 5. White Limestone. 

 Under No. 3 Tate and Barrois both included the zone rich in 

 Inoceramu s-fragments occurring in the next division, but this zone 

 is different in colour and chemical composition, and is practically 

 absent in the Central area, the White Limestone with conglomeratic 

 or nodular chalk at the base resting unconformably on the lower 

 beds. Palaeontologically, all these lower beds are rich in large 

 dimyarian bivalves, especially Trigoni.ce, Area, Cucullcea, etc. — 

 (c) The Eastern Division, extending along the eastern coast from 

 the neighbourhood of Carrickfergus to north of Carnlough, including 

 Islandmagee. The Glauconitic Sands and Yellow Sandstones with 

 chert are present, but generally thinner than the same beds in the 

 Central area. In them dimyarian bivalves are very rare, bracbio- 

 poda of stunted forms, corals, and sea-urchins having been, on the 

 contrary, only found iu them in this eastern region. The Exogyra 

 eohtmba-zone is barely represented, but the Inoceramus Crispin-zone 

 (which Tate thought to be below that of Exogyra columba) attains a 

 thickness of over 20 feet, and evidence is brought forward to show 

 that it overlies the Ex. cohiwba-zone. There is a paloeontological 

 unconformity between the two zones, the Inoceramus-heds passing 

 insensibly into the White Limestone without the intervention of a 



