192 Scientific Proceedings, Royal Dublin Society. 



prices and quick delivery. On account of its quality and 

 cheapness it lias been used in different coastguard stations in 

 Louth and Dublin in preference to the local limestones." (M. 

 Mellon.) 



In the coastguard stations along the east coast the dressings 

 and other cut-stone, especially for long bearings (steps and sills) 

 have been largely procured in the Co. Dublin. Glencullcn granite, 

 " Clogher Head, Co. Louth ; Rush and Malahide ; Ringsend, with 

 some Dalkey stone ; here they were also used for facing ; at Ark- 

 low, Co. Wicklow, and Kilmichael Point, Co. Wexford, with 

 Aughrim stone. Eingsend, with Glencullen stone ; Dalkey, Bray, 

 and Greystones, Co. Wicklow, with Kingstown stone, the first 

 being also faced with punched ashlars ; while the Bray building 

 is faced with very superior rubble. (M. Mellon.) 



All the authorities speak of the Dalkey and Kingstown stones 

 as very durable. Many of the Glencullen stones disintegrate 

 freely ; but, if well selected, stand well, as in St. Paul's Church, 

 <&c, Dublin. 



Whinstones, Eurytes, Felstones. 



In the Ordovicians, to the north of the Co. Dublin, near Bal- 

 briggan, Donabate, andonLambay Island, as also in the southern 

 part of the county, near Saggart and Rathcoole, and in the Cam- 

 brians of Howth, there are dykes and other intrudes, principally of 

 eurytes— that is the rocks intermediate between whinstones and 

 felstones, being neither predominantly basic nor acidic. They may 

 be of the same age as some of the newer eruptive rocks in the Cos. 

 Wicklow, Wexford, and Waterford ; but the precise age of the 

 eruptive rocks near the northern end of the great Leinster granite 

 range is not known ; however, they are post-Ordovieian and pre- 

 Carboniferous. Some varieties, such as that known as the " Lambay 

 porphyry," are a handsome, mottled, green stone, capable of taking 

 a good polish. Specimens were exhibited by the late Lord Mala- 

 hide at different times, some being now in the Dublin and other 

 Museums. The Messrs. Sibthorpe never heard of it being in the 

 market ; but pieces can be obtained by favour, and have been 

 manufactured into paper weights and table slabs of from 12 to 16 

 inches in diameter. At different times during the last 30 or 40 



