Some Igneous Rocks in Down and Antrim. 55 



through one of basalt, which may be seen in the bottom of a 

 deep gully. Between this and Newcastle there are several 

 basic dykes, one large one occurring just below the houses 

 known as the u Widow's Row." 



As the granite of ihe Mourne Mountains is now regarded 

 as probably contemporaneous with the rhyolites of Co. Antrim, 

 I have selected for the first two views in that county slides 

 showing the rhyolite at the east and west ends of the quarry 

 at Templepatrick Railway Station. It was here that Mr. 

 M'Henry obtained the interesting evidence which led him to 

 the conclusion that the rhyolite had intruded in the form of a 

 laccolite into the Lower Basalt series, now regarded as of Eocene 

 age, while further evidence obtained at Ballypaladyand Glenarm, 

 showed it to be older than the Upper Basalt sheets, or, so to 

 speak, of mid-basaltic age.* It is interesting to note that, in 

 this respect, these later observations bear out the view of Sir 

 Richard Griffith, who in his address to the Geological Society 

 of Dublin in 1836, placed the relative age of the " Sandy Brae 

 Porphyry " between that of the " Lower " and " Upper tabular 

 trap." 



The chiei localities in Co. Antrim for rhyolites, besides 

 Templepatrick, are Tardree, Sandy Braes, and Ballymena. 

 Specimens from these districts are on the table, for several of 

 which I am indebted to Mr. Robert Bell, whose fine collections 

 of fossils and rock specimens are well known. 



The next lantern slide shows an exposure of beautifully 

 banded rhyolite in a quarry between Tardree and Sandy Braes 

 and it will be followed by two slides showing a small protrusion 

 of rhyolite at Cloughwater. " The whole mass," Professor 

 Cole writes. " is so small, that it might possibly be a displaced 

 portion of a lava-stream, as it stands we must regard it as 

 representing a volcanic neck." \ 



* " On the Age of the Trachytic Rocks of Antrim," by A. M'Henry, M.R.I. A. 

 Geol. Mag., Dec. 4, Vol. 2, p. 260. 



t The Rhyolites of the Co. of Antrim. By Grenville A. J. Cole, M.R.I.A., 

 F.G.S. Sc. Trans. Roy. Dublin Soc, vol. VI., Ser. II., p. 112. 



