﻿140 PROF. E. W. SKEATS ON THE [Feb. I905, 



Discussion. 



The President said he felt that the Fellows, after listening to the 

 Author's presentation of the work which he had done in great detail 

 in the Tyrol and also in the laboratory, would agree that the Council 

 had made a wise choice when they had made the first award of the 

 Daniel-Pidgeon Fund, 'to be used in whatever way may in their 

 opinion best promote geological original research,' to the Author. 



Prof. Judd congratulated the Society upon the valuable results 

 secured by the first award of the Daniel-Pidgeon Fund, and at 

 the same time complimented the Author on the lucid and effective 

 manner in which he had marshalled his facts and arguments. He 

 bore testimony to the great skill and patience with which the in- 

 vestigation had been carried out* He further ventured to express 

 the hope, that the founder of this Fund would feel satisfied as to the 

 success of the means which she had adopted to carry out the wishes 

 and perpetuate the memory of her late husband. With respect to 

 the arguments of the Author, he pointed out that the very important- 

 conclusion, that coral-rocks yield only minute traces of insoluble 

 residue, was established not only by the Author's own analyses, but 

 by those of several other chemists, including Mr. Stanley Gardiner. 

 That other calcareous sediments contain a sensible proportion — 

 1, 2, 3, or more per cent. — of insoluble residue is proved by the 

 analyses of the ChaMenger-m&teYmh and many investigations of 

 later date. The Author, by an application of the method described 

 in the Funafuti Keport to the classic dolomite-district of the Tyrol, 

 had given a confirmation of the value to geologists of this crucial 

 test concerning the origin of limestones. In addition, he had 

 supplied a number of observations bearing on the very difficult 

 chemical problem of dolomitization, which could scarcely fail to be 

 of service in its ultimate solution. 



Dr. E. F. Armstrong remarked that, in the course of Prof. Yan't 

 Hoff's Stassfurt investigations, with which he had been associated, 

 the problem arose as to the order in which salts would separate out 

 from sea-water. It was a question whether dolomite existed as a 

 true chemical compound, or was merely an intimate mixture of 

 magnesium- and calcium-carbonates. In view of the great number 

 of double salts known to exist, the former hypothesis seemed at 

 least plausible. So much being granted, the problem next arose as 

 to the conditions which governed the separation of dolomite from 

 solution. Here, perhaps, pressure was a more important factor than 

 any other variation that could be suggested. The Author had 

 drawn attention to material containing a small percentage of 

 magnesium-carbonate, but showing no evidence of dolomitization. 

 One explanation might be that, owing to some variation in pressure, 

 or other causes, not dolomite but magnesium-carbonate pure and 

 simple had been deposited from solution ; and it would be inter- 

 esting to know whether this could be distinguished by microscopic 

 methods from calcium-carbonate. It was noticeable, in this con- 

 nection, that the uppermost rocks in the Funafuti borings, where 



