86 Reviews — Iron-ores and Bauxite of N.E. Ireland. 



The lied Marl comes on just to the east of tliis section, at Saffron 

 Lane, where 24 ft. Gin. to 4^ ft. 6 in. of Red Marls, Green Marl, 

 and skerries are exposed, underlying Drift deposits. A few thin 

 bands of tibrous gypsum are present in a thick bed 10-12 feet of 

 nodular lied Marl. Below this comes sandy marl like that at the 

 .south end of the Thurmastoii pit, which suggests that the skerry in 

 the Thurmaston Pottery is Upper Keuper Sandstone. Below "this 

 again the lowest bed is flaky and ferruginous like the bottom bed of 

 Barrow's Pit, Thurmaston (west of the Midland Railway), supporting 

 this correlation. 



In an adjacent pit at Knighton Junction l^rickyard, 36 ft. 6 in. to 

 51 feet of Red Marls aiid Green Marl and skerries, with ball gypsum, 

 is exposed in a fine section of the upper beds. Three beds of gypsum 

 are exposed, two over 1 foot thick. The lowest is encrusted with 

 selenite crystals as at Vass's Pit, Avhich is on the same horizon. In 

 places the line of gypsum is replaced by Green Marl, with which it 

 is often associated generallv. 



Where thick-bedded the Red Marl is similar to that at Gip.sy Lane, 

 District (4). The gypsum is often perforated by holes, as at 

 Bel grave. The under surface has an exterior like that produced by 

 raindrops due to some chemical agency. The gypsum is white as 

 a rule, but tinged red in contact with the Red Marl, and is very hard 

 and like alabaster. There is little fibrous gypsum here. 



{To be continued in our next Number.) 



E.E'VIEl'VvT-S. 



I. — Gkological Survev of Ireland. 

 Thk Intkrbasaltic Rocks (Teon-okes and Bauxites) of North-Ea.st 

 Ireland. 



By G. A. .J. Cole, S.B. Wilkinson, Alexr. M' Henry, J. E. Kilroe, 

 H. .J. Seymour, C. E. Moss, and AV. D. Haigh. Dublin: printed for 

 H.M. Stationery Office by Browne & Nolan, Ltd., 1912. 8vo ; pp. vi, 129, 

 with 6 plates, 23 text-illustrations, and 2 coloured maps. Price 3s. 



Tj^REQUENT mention has been made in memoirs of the Survey to 

 Jj the interbasaltic beds of the North of Ireland, but the recent 

 development of the mineral industry in that area has made a re-survev 

 desirable. The mode of origin of the materials of this consjjicuous 

 zone has been a subject of some discussion, and the first chapter 

 in the present memoir is concerned with the progress of observations 

 in this direction. The origin of similar materials in other regions is 

 discussed, and the conclusion arrived at here is that the bright- 

 coloured de])Osits originated in Eocene or Oligocene times under hot 

 but not arid conditions, similar to those prevailing at present in 

 ti'opical India or Africa. 



In this memoir the area under consideration is divided into four 

 districts — the Northern, East and Mid-Antrim, and the Southern 

 districts. So far as tlie Northern district is concerned the types 

 of deposits are different in character and mode of occurrence, and do 



