528 Scientific Proceedings, Royal Dublin Society. 



however, such things are nearly invariably done by days' work, in limited hours, con- 

 sequently in one case the work can be done much cheaper than in the other, and the 

 goods sent into the market much cheaper. The Belgian chimney-pieces now in the 

 market are enamelled, which was not the case with the Irish chimney-pieces formerly 

 in the market. It is for a similar reason — "cheap labour" — that the Belgian red 

 marbles have cutout, in the English markets, the "Irish reds," although the latter 

 are superior.] 



PERMIAN. 



In a few places there are conglomerates and sandstones said to 

 be of this age ; but in some places those supposed to be Permian 

 are probably Carboniferous, and in others probably Triassic ; they 

 being the upper beds of the first, and the lowest bed of the other. 



TRIASSIC. 



The sandstones, or Redfree, as they are generally called, are 

 free-working stones, and capable of producing fine work. They, 

 however, except in a few places, are not durable, also most of them 

 are liable to discolour ; and although the stones may be selected 

 with great care, yet nearly always some will become unsightly, 

 spoiling the general effect ; still buildings with dressing and quoins 

 of these sandstones, and walling of limestone, or even basalt, have 

 an effective appearance. Exceptions to these general characters 

 are the stones of North Down, Scrabo, and Dundonald, as from 

 these, especially the latter, stones of good repute are procured. 

 The hard texture of these may possibly be due to the associated 

 igneous rocks. 



JURASSIC, CRETACEOUS, EOCENE, AND DRIFT. 



In the groups of strata later than the Triassic the few sand- 

 stones that occur are of little account for building purposes, they 

 nearly invariably being too frail to be thus used. Some of the 

 drift sandstones are only in course of formation at the present 

 time, sand and gravel being cemented together by water percolating 

 through them, charged with carbonaceous, silicious, or ferriferous 

 matter. 



