350 BGientifio Proceedings, Royal Dublin Society. 



those rocks are much older than those with which they are 

 associated. This unconformability, however, does not appear to 

 me to be of any importance, as such is there to be expected ; 

 because agglomerates usually form protrusions in the rocks with 

 which they are associated ; — witness the massive agglomerates in 

 the Carboniferous rocks of Limerick, and elsewhere, and those in 

 the Lower Old Red Sandstone (Silurian) of Cork, Kerry, and 

 Koscommon ; moreover, in the metamorphic rocks of Galway 

 (GaTThhro- Silurian and Cambrian) there are masses more or less 

 similar to that near Greenore ; and to me it would appear absurd 

 to say that the agglomerates in any of these places are more 

 ancient than the associated rocks ; as in each case they belong to 

 the rocks with which they are associated. 



In connexion with the Co. Wexford it may interest enter- 

 prising Laurentianists to suggest to them a new field for inquiry, 

 which is the range of hills adjoining the m earing of the counties 

 of Wicklo w and Wexford, and extending from Croaghan Kinshellagh 

 nearly to Kilcavan, as here there are man}' rocksof Laurentian types. 



West Galway. 

 The rocks in this area I have worked most carefully ; and it 

 was not until after this examination was complete, and after I 

 had carefully plotted sections across them, under the surveillance 

 of Dr. Hull, that my opinion as to their age was matured. These 

 sections were exhibited and explained* at the meeting of the Bri- 

 tish Association in Belfast (1 874) ; and, if these are compared with 

 the sections that have been published of the district, it will appear 

 that the latter, although they are supposed to be taken from my 

 work, are a mistaken misrepresentation of the facts as I have 

 given them. Some of the most important incorrectnesses are, 

 /Irst, the rocks of the ophicalcite series are represented as being 

 above the great quartzites of Bennabeola, while, in every case, they 

 are below them ; second, the rocks now said to be Laurentian — 

 that is, the rocks south of the valley from Clifden to Oughterard 

 — have a general dip southward, or away from the quartzites of 

 Bennabeola. In some places they are inverted and reversed, as 

 pointed out in the Geological Survey Meonoir, while in other 

 places there may be local northward dips due to the transverse 

 faults ; but the main dip is to the south, conformable with that 



* By special permission of the Director-General. 



