564 Scientific Proceedings, Royal Dublin Society. 



The round tower on Devenish, in Lower Lough Erne, is built 

 of local sandstone, and displays good work, with ornamental 

 mouldings at the base of the cone. There is also the very hand- 

 some cross that was exhumed when the tower was repaired about 

 1878. It displays elaborate and careful work. Since it has been 

 placed in its original site it has considerably suffered from the 

 weather. The stone, as already mentioned, seems to have been 

 procured from the Kesh sandstone to the north-east of the lake. 



Sand and (travel. — There is good pit sand near Irvinestown. 

 Good river sand can be procured in many of the rivers and 

 streams. That used at Lisnaskea is brought about two or three 

 miles, and what is used in Enniskillen is principally brought by 

 boat from the Eiver Arney, and from near Pettigoe. There is 

 also good river sand near Irvinestown. 



GALWAY. 



The rocks north of Galway Bay are more or less granitic, and 

 Professor Hull has stated that he considers that they are of Lau- 

 rentian age, this opinion being grounded solely on their lithological 

 characters. Unfortunately for this theory, although the rocks in 

 the vicinity of Galway are more altered than elsewhere in the 

 county, they graduate northward and westward into rocks only 

 slightly altered, the fossils in which prove their true ages. The 

 slightly altered rocks to the northward are not included in Pro- 

 fessor Hull's Laurentians, as in them are found fossils of Ordo- 

 vician type ; those, however, are to the westward. In the latter as 

 yet no fossils have been found, but they have not been properly 

 searched. The fossil evidence in the rocks to the northward proves 

 that these so-called Laurentian rocks are some of the youngest of 

 the metamorphic rocks of the Co. Galway. 



[It is evident that the time of the metamorphism which gives their present 

 gneissose characters to the rocks was post-Ordovician ; also that the granitic and 

 schistose characters of the rocks are solely due to this metamorphic action, and not to 

 the age of the rocks.] 



In "West Galway the Ordovicians appear to have graduated 

 downwards through the Arenig into the Cambrian, so that all 

 are now more or less represented. In the more altered portions 



