Kinahan — On Irish Arenaceous Rocks. 601 



the lower courses are of limestone, but in the adjoining churches, 

 which were subsequently built, limestone was used, Some of the 

 sandstore hereafter mentioned, if known, would be more sought 

 after than it is at present. 



The major portion of the area is occupied by limestone. "We 

 find, however, to the north-east, a little S. S. W. of Birr (Parsons- 

 town), the small but conspicuous hill of Knock sheegowna, mostly 

 Ordovician, but margined to the north-east and south by Lower 

 Carboniferous Sandstone. Somewhat similarly, in the Arva Moun- 

 tains, that lie to the east of the south arm of Lough Derg ; in the 

 group comprising the Silvermine Mountains and Slieve-Phelim ; 

 in Slieve-na-Muck, to the south of Tipperary ; and in the portion 

 of the Galtees that is included in this county there are Ordovicians, 

 margined by Lower Carboniferous Sandstones. The Hill of Cullen, 

 to the north-west of Tipperary, is Loiver Carboniferous Sandstone ; 

 but the rocks of Knockmeeldown, to the south-east of the county, 

 are probably in part Devonians, coming in from the neighbouring 

 Counties Cork and Waterford. 



To the south-east, in the neighbourhood of Killenaule and 

 north-east of it, are Coal-measures, the East Munster Coal-field ; 

 while south-westward of the principal area are small, detached 

 patches as outliers, which lie north of Cashel ; north-east and south- 

 west of Fethard; north-west of Clonmel; in Slieve-na-Muck, brought 

 down by a great fault against the Ordovicians ; and at Ballyporeen, 

 in the valley between the Galtees and Knockmeeldown. 



Ordovician. — These are, in general, in more or less inaccessible 

 positions. When otherwise, nearly invariably the grits are in bad 

 repute, as the associated slate rocks are preferred for local building 

 purposes. 



Devonians. — The rocks of Knockmeeldown seem to be in part 

 the representatives of the Devonians of the County of Cork, that is, 

 the Passage-beds between the Silurians and the Carboniferous; 

 while it is not impossible that the lower rocks of the Galtees to the 

 northward, and of Slievenaman to the north-eastward, may be in 

 part of this age, as the great thickness of the arenaceous rocks 

 under the Carboniferous Limestone, as found in ail these places, sug- 

 gests that the Passage-rocks may be in part represented. 



Knochneeldoivn. In different places brownish, reddish, and 

 yellowish. Free- working ; durable. Has been extensively used in 



