286 Mr. Weaver 07i the Stnicture of the South qflrelandi 



the Slievenamuck and the other ranges more west, which rise 

 in the vale of Limerick (although in fact all connected and 

 belonging to the same formation), are alone coloured as old 

 red sandstone (reddish and yellowish-brown*.) 



A few remarks here upon the construction of sections mixy 

 not be misplaced. In my sections through the south of Ire- 

 land I have endeavoured to combine two objects, namely, to 

 give outlines of the actual forms of the surface presented by 

 nature, and to represent faithfully the relative position of the 

 successive mineral masses, employing as nearly equal scales 

 for heights and distances as the engraving would permit, the 

 difference being only as four to three; but I have not at- 

 tempted to introduce the differently modified structure of 

 their respective stratification, and for two reasons: 1st, that 

 to do it correctly upon any given transverse line according 

 to scale and measure, would require considerable labour, and 

 even when accomplished might not exactly accord with the 

 results of an examination conducted on parallel lines in differ- 

 ent longitudes, in a country where the stratification is more 

 or less fluctuating; 2nd, that unless done correctly, such sec- 

 tions, instead of conveying precise information, tend rather to 

 mislead the judgement. In such cases, it appears more judi- 

 cious to supply the deficiency by adequate description. 



Now, it is for the second of these reasons that I must ob- 

 ject to Mr. Griffith's sections. They appear to me in many 

 respects drawn rather according to the conceptions of their 

 author than the occurrences in naturef. As some proof of 

 this, I will in the first instance take the section which is 

 drawn through the south-eastern part of the island, beginning 

 at the valley of the Suire (where it first intersects the car- 

 boniferous limestone), and following it to its extremity in the 



* In the new map the Gaultees are now also coloured reddish brown, as 

 old red sandstone. 



f The same remark applies to the sections drawn in Kerry by Mr. C. 

 W. Hamilton also, but especially so to the section No. .3 in his "Outline 

 of the Geology of part of the county of Kerry," in the Journal of the Geo- 

 logical Society of Dublin, vol. i. pp. 276 to 285, in which there is nowhere 

 drawn a clear distinction between the conglomerates and sandstones of the 

 transition series and those of the old red sandstone formation, the one 

 being confounded with the other. Moreover, in No. 3 section, the old red 

 sandstone and the coal measures are confounded together, the latter 

 (north of Tralee) being made to underlie and break through the carboni- 

 ferous limestone instead of reposing upon it, and the text in p. 284 is to 

 the same effect. This is the paper referred to by Prof. Sedgwick and Mr. 

 Murchison in the Lond. and Ediu. Phil. Mag. in April 1839, at p. 260, and 

 to which I had occasion to advert in the same Magazine for August, 1839, 

 at p. 122. Two later sections in Kerry, given by Mr. C. W. Hamilton in 

 the Lond. and Edin, Phil. Mag. for Dec. 1839, are not only open to tjie 



