KiLROE — Silurian and Metamorphic Bocks. 



157 



Hill, near Louisburgh, to Eclclare, south-west of AVestport, may be 

 seen at intervals, always in the same position relatively to the 

 quartzite, massive conglomerates containing almost exclusively 

 pebbles of banded quartzite, of all sizes up to 3 feet in length by 15 

 to 18 inches across, crushed, compacted together, and elongated by 

 compression in a very remarkable way, and set in a highly- silicified 

 matrix. On a previous page a note was cited from the 6 -inch 

 working field-map (made by the original surveyor, who was quite 

 unaware of conclusions such as the present with regard to the range) 

 to the effect that the conglomerate here described resembles that at 

 Knockfadda ; which, it will be remembered, underlies quartzite, as is 

 the case with stratigraphically corresponding beds at Cregganbaun. 



If a section be taken along the stream which drains the hill, and 

 flows north by Leckanvy K. C. chapel, the conglomerate, about 70 feet in 

 thickness, appears with the commencement of the steeper slope above 

 the drift-covering ; and it rests upon quartzite which forms a down- 

 ward series, while the stream flows northward. The series dips at a 

 high angle, must be of considerable thickness, and, striking south- 

 eastward, it is seen to form the peak of Croagh Patrick. 



The stream before turning northward flowed north-westerly upon 

 a band of calcareous slate and sandstone, which are considerably 

 cleaved, generally in accordance with the bedding, but not mineralized. 

 The original characters of the beds are so well preserved, notwith- 

 standing cleavage, that little difficulty is experienced in recognizing 

 in them, on lithological grounds, the counterparts of those already 

 described which yielded fossils at Boheh similar to those at Creggan- 

 baun. This conclusion was verified by the discovery in 1893 of a 

 turbinated coral, of a type plentiful at Cregganbaun. Two recent 

 visits to the ground, the second in company with the present Director 

 of the Survey, have resulted in further unquestionable confirmation, 

 when seams of calcareous argillaceous sandstone came to light, bearing 

 a rich fauna of corals {Feiraia, Favosites, &c.), graptolites, and trilobites. 

 The forms of the latter two groups are just recognizable, but scarcely 

 sufficiently so to warrant naming. 



The beds containing these fossils dip beneath the quartzite of 

 Croagh Patrick peak, just as the continuation of this, in the Lecanvy 

 stream, dips beneath the conglomerate ; and from what has been 

 explained above, there is no longer any room for question that this 

 important portion of the range is made up of the three members of the 

 Cregganbaun group, though in inverse order of occui-rence. 



The fossil-bearing beds, shown as mica-schist on the published map, 

 are there represented as faulted against quartzite on the south side, 



