710 Proceedings of the Royal Irish Academy. 



Westwards of tHs chain of mountaiiis the land subsides to lower 

 levels along Blacksod Bay and Bellacragher (Ballycroy) Bay. The 

 latter winding, narrow estuary, runs down from the northwards to 

 within an English mile of Clew Bay on the south. This peninsula, 

 about six or seven miles in diameter, is called Curraun Achill, and is 

 separated by the narrow strait of Achill Sound from Achill Island. 

 Curraun Achill is known to botanists as being the head-quarters of the 

 Mediterranean heath in Ireland. It is all mountainous : consisting of 

 a detached peak (1500 feet) in the northern part, which I did not 

 examine, and a wide table-land at about 1300 feet, rising in places to 

 1700 feet, above sea level, which includes the chief southern part of 

 the promontory. This table-land is composed of quartzite, and subse- 

 quently of horizontally stratified sandstones and conglomerates, which 

 break away into regular terraces along its north-eastern edge of a 

 picturesque and unusual character. This sandstone is, I believe, 

 lower carboniferous ; it soon, however, gives place to the perpetual 

 quartzite forming the greater part of Curraun. On the table-land, at 

 1200 feet, Arctostaphylos, Empetrum, and Juniper form a carpet, 

 the first and last being remarkably abundant. At a greater height 

 Salix herlacea and Carex rigida were, as usual, met with, and with 

 these a rarer alpine species, Lycopodium alpinum, which was only 

 seen in two or three places in the west. 



Ctjeeahn" Achill, down Noeth-east. 



1560 feet. 



Salix herbacea. | Carex flava. 



Lycopodium alpinum. 



1200 feet. 

 Lotus corniculatus. 

 Arctostaphylos ' uva-ursi . 

 Armeria maritima. 



Plantago maritima. 

 Empetrum nigrum. 

 Juniperus nana. 



200 feet. 

 Hymen ophy Hum tunbridgense. | H. unilaterale. 



150 feet. 

 Erica mediterranea. 



South of Feeet, neae Sea Level. 

 Sparganium natans. | Ehynchospora alba. 



The Island of Achill is shaped somewhat as a right-angled triangle, 

 the shorter sides running due north and south, east and west. From 



