the Counties of Mayo and Sligo in Ireland. 151 



into Tyreragh, behind Skreen hill. On both sides, the foot of the mountain is covered by a 

 stratified quartzose conglomerate, which extends as far as the pass of Lough Talt. 



The next communication between the baronies of Liney and Tyreragh, is through the mountain 

 valley in which lies Lough Eask, the source of the river Eask. A small patch of granite borders 

 the road which passes along the east shore of the Lough. 



The river Moy having received, before it reaches Foxford, an accession of water from the 

 Guishaden, as well as the lakes Conn and Cullen (about forty feet above high-water mark), passes, 

 below the town, through the mountain chain between Carrick o'Hara and Shraheen Hill. The 

 course of this river from its source to the Atlantic below Ballina, is about thirty Irish miles ; and 

 the descent being 300 feet from its head to high-water mark, it has a fall of ten feet in the mile, 

 or one-sixth of that of the Colloony river ; and probably from this cause, the effects of the stream 

 are less striking, the pass through the mountain chain being also less abrupt : the soil likewise has 

 not been so entirely removed as at Colloony. 



Foxford stands on gneiss, from below which mica slate rises, at the hills of Shraheen and Bur- 

 ran on the Moy. Lough Cullen communicates with this river near the town, having received 

 the drainage of Lough Conn, by the rocky strait at the Pontoon, where the waters have forced a 

 passage through the beds of gneiss, leaving immense boulders scattered on the surface, even to 

 the summit of the hills over the pass. 



It is remarkable, that throughout this district clay slate is never found either in situ or boulders. 



In the cliffs along the sea coast (see PI. XL) the succession of strata is 

 satisfactorily exposed. Commencing at the promontory of Tarmon in Erris, 

 a district where primary rocks only occur, granite is quarried near Blacksod 

 Point, and lies in beds which may indeed be called strata. The felspar is 

 brick red, the quartz smoke grey and translucent, and the mica black : no 

 imbedded minerals have been observed. In a small inlet on the shore, at 

 the west end of the hill, below the Signal Tower, mica slate appears, dipping 

 15° to the east, and abuting against the face of the granite beds, which 

 incline to the west 45° ; and in a narrow cove, south of this inlet, the dip 

 of the mica slate increases to 70°, its direction becoming south. Numerous 

 veins of granite penetrate the slate, and in some instances contain fragments 

 of it. 



Proceeding to the north-east, the coast presents only a succession of sand- 

 hills and beaches, except where a few reefs of gneiss or mica slate project into 

 the sea. The first range of cliffs is at Annagh, the south headland of French- 

 port, and consists of mica slate traversed by a trap dyke ; but the north head- 

 land of this inlet is formed of gneiss, composed of red felspar and black mica. 

 On approaching Scotchport, garnets appear, the mica increases, and the felspar 

 gradually diminishes, till the gneiss becomes mica slate, which graduates into 

 quartz rock, in the direction of Erris Head*. This formation constitutes the 

 lofty and broken cliffs to Broad Haven, with the exception of a few places, 



* For additional observations on this part of the coast see p. 160. 



