268 Scientific Proceedings, Royal Dublin Society. 



Batty cottin Bay. 



Grey flint. — Antrim, or possibly bed of Irish Sea. 

 Hornblende granite, with conspicuous sphene. — Like granite 



from Camlough Mountains, County Armagh. 

 Gabbro. — Like 'eucrite' of Slieve Trasna, County Louth. 

 Andesite (?). — Silurian area of Waterford and Wexford. 



Whiting Bay. 



Flint. — Antrim, or possibly bed of Irish Sea. 

 Bored limestone. — Bed of the sea. 



Felsite (?) . — Similar to ' felsites ' from County Water- 

 ford. 



In addition to the boulders from the marl, a number were also 

 collected from the modern shore beneath the cliffs of marl. The 

 same kinds of rock occur in about the same proportions, and there 

 can be no doubt that most, if not all, of these have been washed 

 out of the marl or raised-beach gravel. The riebeckite-eurite of 

 Ailsa Craig, the occurrence of which so far south is of interest, has 

 not been found in the marl up to the present. Beyond the most 

 westerly limits of the marly boulder-clay in Ballycroneen Bay, 

 pebbles of flint and igneous rock were here and there picked up 

 on the beach. These pebbles may have come from the pre- 

 glacial beach, or may have been brought by floating weed or ice 

 after the land-ice had melted away. 1 



List of Boulders from the Modern Beach. 2 



Ballycroneen Bay. 



Riebeckite-eurite.- — Ailsa Craig. 



Biotite granite. — Like that of Glenmalure, County 



Wicklow. 

 'Granite, with yellowish felspars (two specimens). — Like 

 that of Great Saltee Island. 



1 Mr. G. H. Kinahan informs us that a quantity of flints were brought to Valentia 

 Island as ballast by ships -which took away slates, and that the flints found on parts of 

 the shore of Sherkin Island, off Baltimore, were probably brought there in a similar 

 manner when the slates in that island were worked. Pebbles and blocks (sometimes 

 dressed) of the Dalkey granite are found on the shore near the lighthouses. This rock 

 has been used in their construction. 



2 This list includes only those rocks whose probable place of origin and parent rock 

 have been recognised. 



