On the Iron-ores and the Basalts of the North-east of Ireland. 73 



that the chalk found in it (equal, according to him, to a layer of at 

 least 200 feet over the entire Wold) could only have been detached 

 by the agency of moving ice, which he believed to have covered 

 nearly the whole Wold for a long period. 



The author stated that boulders of Shap Fell granite are confined 

 to the deposit of clay without chalk, and discussed the means by 

 which they could have been distributed. He ascribed their disper- 

 sion to the agency of floating ice during an adequate submergence of 

 the district. He supposed them to have passed from Shap Pell by 

 what is now the pass of Stainmoor. 



Thus he ascribed the formation of the " Great Chalky Clay " to 

 the extrusion from the sea-foot of a great sheet of ice, of mate- 

 rials abraded by the latter, the land being depressed 600-700 feet 

 below its present level; and that of the clay without chalk and 

 with boulders of Shap-Fell granite to deposition during a period 

 of much greater depression (about 1500 feet), throughout which the 

 sea bore much floating ice. He considered tbat the " Great Chalky 

 Clay" indicated a long period during which the land, with its 

 enveloping ice, remained stationary, and that during this period, 

 when intense cold prevailed, the arctic fauna of Bridlington be- 

 came established. He thought that the recommencement of sub- 

 sidence was indicated by the reddish-brown or brownish-purple 

 sediments of Holderness, in which some chalk occurs. He then 

 indicated the species of Mollusca which have occurred in the purple 

 clay without chalk about Scarbro' and Whitby, all of which were 

 said to belong to existing forms, and thus to be in accordance with 

 the date assigned by him to that deposit. The molluscan fauna of 

 Mocl Tryfane was referred to by the author, who stated that he 

 regarded it as belonging to the period of emergence from the 

 deepest depression, during which the clay without chalk was as- 

 sumed to have been deposited, i. e. to the earliest part of the post- 

 glacial period, to which the stratified drifts of Scotland are referred 

 by Mr. A. Geikie. 



December 22, 1869.— Professor Huxley, LL.D., F.R.S., 

 President, in the Chair. 



The following communications were read : — 



1. " On the Iron-ores associated with the Basalts of the North- 

 east of Ireland." By Ralph Tate, Esq., Assoc. Linn. Soc, F.G.S., 

 and John S. Holden, M.D., F.G.S. 



The authors introduced their account of the iron-ores of the 

 Antrim basalts by stating that since 1790 an iron band had been 

 known in the midst of the basalt of the Giant's Causeway, but that 

 only within the last few years have further discoveries been made, 

 which have developed a new branch of industry in the north-east of 

 Ireland. 



The iron-ore of the numerous exposures was considered to repre- 

 sent portions of one sheet extending uniformly throughout the basalt 

 and over a very large area. Indeed everywhere the iron band and 



