Reports & Proceedings — Edinburgh Geological Society. 235 



III, — Edinbuegh Gkological SociETr. 

 Felruary 19, 1913,~Dr. John S. Flett in the Chair. 

 The following communications were read : — 



1. " The Geology of Raasay." By Mr. H. B. Woodward, F.R.S. 

 Communicated by Dr. John Home, E.E..S. 



The oldest rocks belong to the Lewisian Gneiss, and these are 

 covered unconformably by the Torridon Sandstone, which includes 

 representatives of the lower and middle divisions of that sj'stem. 

 No Palaeozoic rocks have been recorded in Kaasay, but there is 

 a splendid development of Mesozoic strata ranging from the Trias to 

 the Great Oolite. The characteristic features of the Trias, the lower, 

 middle, and upper divisions of the Lias, the Inferior Oolite, and the 

 Great Estuarine Series were indicated. Mr. "Woodward referred 

 specially to his discovery of a band of oolitic limestone near the top 

 of the Middle Lias, and approximately on the horizon of the well- 

 known Cleveland ironstone of Yorkshire. The igneous rocks of 

 Tertiary age occurring in Raasay and the prominent faults or dis- 

 locations affecting the strata were described. 



2. "The Raasay Iron-ore." (Illustrated by diagrams, lantern 

 plates, rock sections, and specimens.) By Mr. Wallace Thornycroft. 



In his paper on the Eaasay iron-ore Mr. Wallace Thornycroft 

 stated that Mr. Woodward had drawn his attention to the account of 

 the discovery of the Eaasay iron-ore published in 1893. Having 

 made arrangements with the proprietrix of the island, he began to 

 prove the field by a series of bores, which were under the direction 

 of Mr. Campbell as mining engineer, with the co-operation of 

 Mr. C. B. Wedd, of His Majesty's Geological Survey. The results 

 of these operations proved that the thickness of the ironstone was 

 much greater than that indicated by Mr. Woodward, and that it 

 covered a much larger area. By means of comparative vertical 

 sections of the various bores he showed that the thickness of the 

 deposit ranged from 6 to 17 feet. The quality varied somewhat, 

 especially in the contents of lime. Generally speaking, it appeared 

 that the percentage of lime increased towards the outside limits of 

 the deposit, and the percentage of iron increased with the thickness. 

 When compared with the Cleveland ore it was found that the Eaasay 

 stone contained more lime and phosphorus than the former, but 

 rather less iron, and less silica and alumina. Reference was made to 

 the faults shifting the outcrop of the band of ironstone, and to the 

 relation of the intrusive masses of granophyre to the ore deposit. 

 Mr. Thornycroft stated that the horizon of the ironstone underlay 

 the whole of the northern part of Skye, and extended under the sea 

 as far as the islands of Eigg and the Shiants, but it remained to be 

 proved whether any ore in that position was ever formed outside the 

 limited area of Eaasay. He showed by sections of outcrops in Mull 

 and the south-east of Skye that the ironstone had not been formed at 

 the points visible, and that even if the iron-ore had been developed 

 it would have been rendered unworkable by the intrusions of 

 igneous rock. 



