THE 



LONDON and EDINBURGH 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[THIRD SERIES.] 



SEPTEMBER 1840. 



XXV. Reply to that part of Mr. Weaver's Paper relative 

 to the Mineral Structure of the South of Ireland, which has 

 appeared successively in the Numbers of the Philosophical 

 Magazine for April, May, and June, 184-0. By Richard 

 Griffith, F.G>S. London and Dublin*. 



[With a Plate.] 



1LTAVING read with much care Mr. Weaver's paper 

 AJ - published in successive Numbers of the Philosophical 

 Magazine, relative to the mineral structure of the south of 

 Ireland, &c, in which he endeavours to support his own 

 views t in opposition to mine, respecting the order of succes- 

 sion of the rocks, and the geological position to which each 

 is referable, I think it incumbent on me briefly to reply to 

 those views and statements, which are quite inconsistent with 

 facts carefully observed by me, and represented in my large 

 geological map, as well as in several sections, exhibiting what 

 appears to me to be the true order of succession of the strata 

 of the south of Ireland: some of these sections have been 

 published in the Journal of the Geological Society of Dublin J, 

 and others in the Numbers of this Magazine for March last. 



As the boundaries of the several rock districts as repre- 

 sented on the map, and their relative positions as exhibited in 

 the sections, differ materially from those published by Mr. 

 Weaver, they are considered by him to be imaginative com- 

 positions, and consequently unworthy of credit ; but I hope 

 to be able to prove that my map and sections are founded 

 solely on a careful observation of facts, and in no case from 

 hypothetical deductions. 



* Communicated by the Author. 



t See vol. v. Transactions of the Geological Society of London, second 

 series. J See vol. ii. part 1. 



Phil Mag. S. 3. Vol. 17. No. 109. Sept. 1840. M 



