Notices respecting New Books. 63 



at Woodburn, which cuts through greensaiid and chalk, both 

 becoming crystalline near the dyke, and says that the existence of 

 the Glauconite (a hydrosilicate of iron and potash) in a limestone 

 which has become crystalline from the contact of trap, " entirely 

 excludes the hypothesis of that crystallization being the result of an 

 action exclusively igneous." 



His remarks on the metamorphic action which the trap or whin- 

 stone of the neighbourhood of Edinburgh have produced on the grits 

 of the Carboniferous formation there, are very interesting. The 

 specimen of whinstone examined by M. Delesse contained — 



Residue insoluble in acid 6650 



Water 288 



Carbonic acid 6* 86 



It made a considerable effervescence when plunged into acid, con- 

 taining carbonates of lime, of iron, and of magnesia. The great 

 quantity of carbonic acid in the trap, he thinks, might have been 

 the result of intiltrations of carbonate of lime, jjroceeding from the 

 calcareous grit into which the trap was injected. This calcareous 

 grit was, indeed, rather a sandy limestone than a grit, as iM. 

 Delesse observes ; for it contained 66'19 per cent, of carbonate of 

 lime. He particularly points to the apparent presence of a mixture 

 of zeolite in the grit when near to the trap ; and finishes his remarks 

 on the metamorphism of the siliceous rocks, by calling attention to 

 the fact of the frequent development of hydrated minerals, proving, 

 £is he believes, that in this metamorphism the " premier role" does 

 not belong to igneous but to aqueous action. 



^His account of the action of the trap at Portrush in the North of 

 Ireland, is given in the following abstract : — 



" At Portrush, in the north-east of Ireland, we find a rock which 

 at first sight appears to be trappean, and w'hich nevertheless con- 

 tains well-preserved fossils. 



"The partisans of Werner, Kirwan, Dr. Richardson, and Du- 

 bourdieu liken this rock to a basalt ; they conclude, therefore, from 

 the presence of fossils, that basalt has an aqueous origin, and was 

 formed at the bottom of the sea. 



" The partisans of Hutton, Sir James Hall, Playfair, Dolomieu, 

 contend, on the contrary, that the rock of Portrush was deposited 

 in the bosom of the waters, and has since been modified by an 

 igneous action. 



" At a more recent epoch, the deposit of Portrush has been studied 

 with much care by Messrs. Conybeare, Buckland, Jiryce, Oldham, 

 but above all by Mr. (now Sir Richard) Griffith and Colonel (now 

 General) Portlock. 1 visited it myself in 1852 ; and I proceed 

 to give a summary description of it, and will afterwards inquire 

 what were the alterations undergone by the metamorphic rock of 

 Portrush." 



He then states that the base of the promontory is formed of a 

 greenstone, which reappears in the Skerries, and that on this reposes 

 a stratified rock whicli has l)ecn called " chert, flint-slate, siliceous 



