l62 



ihc Irish Naturalist. 



rocks, which extend far to the west and north, are completely 

 excluded from its basin by the granite of the Leinster 

 chain. (See Map, fig. i.) 



Fig. i. 







-» ^H* j * ^ ' * ***** 



A . ■ V • / • < * 







CAMBRIAN 





ALTERED 

 ORDOVICIAM 



GLACl/\LDRIfT 



ORDOVICIAN 



* -V \ -V * 



CRANITE 



ALLUVIUM. 



Starting from the sea, we will follow the road to Ennis- 

 kerry, which runs first on the northern bank of the stream, 

 and for the latter half of its distance on the southern ; and 

 study the sections in the order in which we meet them. The 

 first section is seen by the roadside opposite Bra)' Common. 

 Here the drift presents steep faces some fifteen feet in height, 

 and consists of sandy clay and coarse boulders confusedly 

 intermingled, without stratification, traversed by vertical pipes 

 filled with coarse but otherwise similar material. The stones 

 consist of green diabase, porphyritic with felspar (Lambay 

 porphyry 1 ), Leinster granite, and Carboniferous limestone, all 



1 This rock, commonly known as " Lambay porphyry," forms a large 

 part of Lambay Island, fifteen miles N.W. of Dublin, and is common 

 in the Ordovician rocks of Eastern Ireland ; near Dublin it occurs in 

 numerous dykes at Glennasmoil. 



