506 Alfred Earler — Igneous Rocks of 8kije. 



concentration. When it is remembered that the Dead Sea sinks to 

 depths of 400 metres we may realize that very great deposits must 

 be supposed existing immediately around and beneath its waters 

 if Mr. Ackroyd's views are to be entertained. The fact quoted by 

 Mr. Ackroyd that " common salt in the southern parts of the lake 

 forms quite a paste " will evidently not suffice. 



It is needless to^quote here the views of geologists on this question. 

 The observations of Lartet (Bull. S.G.F., [2] xxiii, p. 719) quoted 

 by De Lapparent show that " tous les sels contenus dans I'eau do 

 la mer Morte et celle du Jourdain sont egalement (a I'exception 

 peut-etre du brome) renfermes dans les eaux des sources chaudes du 

 meme bassin, notamment celles de Zara, de Callirhoe, et d'Emmaiis " 

 (vol. i, p. 488). The absence of iodine, so characteristic of sea- 

 water, the presence of bituminous and sulphurous odours, the very 

 local variations in composition, further lead M. de Lapparent to 

 the view that the intervention of sea-water cannot be looked for in 

 accounting for its composition ; but that it represents a fresh- water 

 lake modified by volcanic agencies of comparatively recent date. 



Having no leisure to discuss the matter further, I would close my 

 remarks by stating once more that the carriage of sea-salts into 

 many inland lakes is very certainly a fact. The difference between 

 Mr. Ackroyd's and my own views on the matter is one of degree 

 only. If my own original estimate, that 10 per cent, of river 

 chlorine is from the ocean, were correct, this would involve con- 

 siderable importations of sea-salts in process of time into inland 

 waters. 



V. — The Sequence of the Tertiary Igneous Eocks of Skye. 

 By Alfred Harker, M.A., F.G.S. 



(Published by permissiou of the Director of the Geological Survey.) 



THIS communication is the outcome of work carried out during 

 the years 1895-1901 in the service of the Geological Survey 

 of Scotland. Although this systematic work has been confined to 

 the Isle of Skye, information incidentally acquired, and the published 

 literature of the British Tertiary rocks, indicate for the conclusions 

 arrived at a much wider application. In this place the results must 

 be set down without the detailed observations upon which they 

 are based. 



Here, as in numerous other areas and at various geological periods, 

 igneous activity has manifested itself successively under three 

 different phases, the Volcanic, the Plutonic, and the Phase of Minor 

 Intrusions (often called the Dyke Phase). There is further an 

 important distinction to be observed, neglecting which the whole 

 sequence is thrown into confusion. The various events recorded in 

 the succession fall into two distinct categories of very different orders, 

 which may be termed the Begional Series and the Local Series. 

 Those of the former class affected a very wide area — perhaps in 

 some cases the whole Brito-Icelandic Province, extending from the 



