586 Scientific Proceedings, Royal Dublin Society. 



much note, although in various places there are quarries. When 

 of fair sizes, they are worked for local purposes. Although the 

 stones are hard, some of them dress fairly well. 



Carboniferous. — According to Traill, the sandstones near 

 Carlingford are not of much value. (G. S. M.) 



Kilpatrick. Near Ardee. — Grey, weathering pale-brown, cal- 

 careous cement ; used for building purposes. Similar rocks are 

 exposed in the bog, two miles N. N. W. of Ardee. (G. S. M.) 



In the celebrated ecclesiastical ruins of Mellifont and Monaster- 

 boice the sandstone dressing used, according to Wilkinson, seems 

 to be Carboniferous Sandstone from the Co. Meath. They and 

 the two large crosses at the latter place are in good preservation, 

 except some badly-selected micaceous stones. In St. John's Gate, 

 Drogheda, the unequal weathering of sandstone and limestone is 

 illustrated. Where the sandstone came from is not known. 



[Mr. Sharpe, the well-known Dublin builder, who has carefully traced up the sand- 

 stones in some of the ancient buildings, is of the opinion, as already mentioned (Intro- 

 duction, page 510), that the stones at Mellifont are from Doulting, near Glastonbury.] 



Sand and Gravel. — Good pit sand occurs near Ardee, and a 

 loamy sand near Dundalk. 



River sand is obtained in the Boyne, at Oldbridge, for use in 

 Drogheda. 



On the coast are dunes and tracts of .ZEolian sands, at one time 

 in request as an agent for making the stiff clays of the county 

 friable. They seem now to be very little used ; they ought, 

 however, to be valuable fertilizers. 



MAYO. 



To the south of Clew Bay are metamorphic rocks, with subor- 

 dinate intrudes of granite. These, to the south and eastward, are 

 overlaid by Silurian or Carboniferous rocks. North of Clew Bay, 

 occupying the north-west portion of the country, and extending 

 in a narrow tract eastward by Westport and Castlebar across the 

 county into the Co. Sligo, there are also metamorphic rocks and 

 granites, which are overlaid either by Silurian or Carboniferous. 



Of the metamorphic rocks in the east and north-west portions 

 of the county it has been stated that they are of Laurentian age ; 



