150 Archdeacon Verschoyle on the Geology of the North Coast of 



depth J and rarely reach to the base of the chain, being gradually lost in the 

 slope of the sides. On the south-east, the ascent is more gradual, less rocky, 

 and streams are more numerous. The principal passes through the range, are 

 from CoUoony to Ballisadere; from Coolany to Baltra by Carrick-na-Shouock; 

 from the barony of Liney to Skreen by Knock-a-Chree; from the same barony 

 to Easky by Lough Eask ; from Tubbercorry to Ballina by Lough Talt; and 

 the Pontoon near Foxford. 



The first, at Colloony, is very picturesque from the magnificent falls of the river over the limestone 

 at Colloony and Ballisadere, and the much shattered and broken mountain of mica schist, called 

 theUnionRock, which rises through the Union Wood; as if a course had been opened for the river by 

 some violent convulsion, the further effect of which has evidently excavated the Bay of Ballisadere, 

 assisted by the subsidence or removal of the limestone. The rocks surrounding Glen Lough at the foot 

 of Benbulben, indicate a similar subsidence. On the south side also of the Ox range, the soil and 

 even the strata of limestone, have been removed, and have probably formed materials for those 

 immense ridges of water-worn gravel, called eskers, which are found in every part of the country. 

 Near Tubbercorry, the surface for a considerable extent, is an almost naked limestone rock, like 

 the shore of the barony of Tyreragh, presenting the same rounded cavities in the surface, as well 

 as the same water-worn aspect, wanting only the sea-weed and the recent shells, to complete the 

 identity. The drainage of this district is through the pass at Colloony, by the Owenmore, which, 

 rising from the west side of Cash Corran, receives at the Union Wood the River Arrow, and be- 

 fore it reaches Colloony that from Coolany, whose source is near Knock-a-Chree. The steep 

 and rocky escarpments of the passes through which these streams flow, with the debris scattered 

 over the surface, mark the effects of a powerful torrent. At the falls of the river, at Colloony, 

 the limestone ceases, and thence to Ballisadere mica slate is laid bare, to a depth of fifty-five or 

 sixty feet, lower than the limestone above the falls. The bank of the river at Coolany, about 

 five Irish miles from the sea, is 298 feet above high-water mark, and the average descent is, 

 therefore, 59*6 feet in the mile. The grey peak above the Union Wood and the precipices of mica 

 slate which skirt the river below, are memorials of the ruin which has taken place; while the frag- 

 ments of the same rock so abundantly strewed in large boulders on the opposite side of the estu- 

 ary of Ballisadere, exhibit both the effect and the direction of the torrent, which evidently flowed 

 from the south-west into Galway Bay, spreading thence to the north-east towards Foxford and 

 Sligo, as indicated by the perpendicular faces and broken strata of the limestone mountains, pre- 

 sented to the south-west and west; by the caves in Cash Corran, perfectly resembling those into 

 which the waters of the Atlantic rush along the coast of Erris ; and especially by the direction 

 of the ridges of limestone gravel throughout the baronies of Liney and Corran, and the southern 

 part of Mayo. 



The second pass, Carrick-na-Shouock, derives its name from a bold and precipitous rock, which 

 serves as a landmark to the harbour of Sligo, rising perpendicularly on three sides, and on the 

 fourth with a very steep and difficult ascent. The road through the pass, winds over successive 

 strata of quartz rock, gneiss, and mica slate, dipping to the south-east, and presenting to the 

 north-west the broken edges of the beds. 



Proceeding westward, we next reach the pass of Carrow-na-Skea, which crosses the ridge below 

 Knock-a-Chree, the highest summit of this chain (1714 feet), and on the north side descends 



