1866.] HAEENESS— GALWAY. 511 



that portion of the limestone which has been least affected by meta- 

 morphic action. This is the character of the limestone which 

 occurs in that portion of the calcareous band which lies east of 

 Lisoughter, and which extends to near Oughterard. In this portion 

 of the band the laminse have not been opened and broken by con- 

 tortions ; and from it the serpentine is absent, and with this absence 

 of serpentine and its associated skeletons of tremolite and asbestos 

 everything like the so-called organic structure disappears. 



The fossihferous Silurian rocks of Connemara and of Joyce's county 

 have been referred to by Mr. J. Kelly in a memoir " On the Grej^- 

 wacke Rocks of Ireland"*. They usually occur on the northern side 

 of the metamorphic range ; but there is one locality where this is 

 not the case — namely, on the western shore of Lough Corrib, at a 

 place called Shanballymore, about three miles north of Oughterard. 

 Here, to the north of a small patch of rather fine-grained granite, 

 and to the east of the metamorphic rocks, the fossiliferous Silurian 

 rocks are seen, consisting of a grey flaggy bed associated with thick- 

 bedded strata ; but their relations to the rocks which margin them 

 arc not seen here, and the fossils are principally procured from the 

 stones in the walls, which have been obtained from the loose frag- 

 ments scattered about the fields. Another fossiliferous Silurian 

 locality lies at the northern end of Lough Corrib, a short distance 

 west of Cong. At the western extremity of this area the strata 

 come in contact with the metamorphic rocks of Benlevy (1375 feet), 

 and the relations of the fossiliferous beds to the rocks which margin 

 them are well seen. Here, at a short distance to the west of Lough 

 Coolin, which hes under the eastern side of Benlevy, Silurian grits 

 occur nearly horizontal in position, but with a slight inclination 

 toward the N.N.E. Immediately west of these grits is one of the 

 bold escarpments of Benlevy, composed of gneissose rocks, which 

 strike east and west and are vertical in position. 



Another locality from which we obtain information concerning the 

 relations of the metamorphic and the unaltered Silurian rocks is in 

 the valley which leads from Maame to Leenane, the latter being on 

 the south shore of Killery Harbour. In this valley there is a stream 

 which flows from the north near Munterown, about three miles S.E. 

 of Leenane. Where the road crosses this stream, at the bridge, a 

 conglomerate in the fossiliferous Silurian strata is seen ; it abounds 

 in well-rounded fragments of gneiss and quartz-rocks, which have 

 been derived from the metamorphic series. 



On the south side of Killery Harbour, at the head of a valley 

 called Glencraff, which runs from east to west, their relations are 

 also seen. The fossiliferous Silurian rocks form the hills on the 

 north side of the valley ; they are well exposed, distinctly bedded, 

 and have an average dip towards the JST.W. at 35°. The south side 

 of the valley consists of hills of gneissose rocks, with strata con- 

 torted, but having the usual east and west strike. 



At Blackwater Bridge, on the road from Leenane to Chfden, and 

 about three miles from the head of Glencraff, Silurian conglo- 

 merates are again seen, containing rounded metamorphic rocks ; and 

 * Journ. of the Geol. Soc. of Dublin, vol. viii. 



