402 Scientific Proceedings, Royal Dublin Society. 



exhibited in the ornaments manufactured by the M'Donnells of Clif- 

 den — self-taught artists — who manufacture brooches and various 

 other articles of vertu by hand, out of ophialytes from these and 

 all the other localities, to dispose of them to visitors. One unique 

 and beautiful variety on sale by Alick M'Donnell was a maculate 

 Sienna-colour ophialyte from a vein at Loughauna. To work the 

 stone in this valley, that to the westward, near Loughauna, 

 could best be approached by a road constructed from Streamstown 

 Bay, from where it could be carted to Clifden for shipment ; while 

 that at Loughnahillion would be brought more easily by a road 

 northward to Barnaderg Bay. 



To the south and south-eastward of the valley last mentioned, 

 and nearly parallel to it, is that of the Owenglin; where, in 

 occasional spots for a distance of over three miles, the ophialytes 

 appear. They are, as elsewhere, most varied in colour and beauty, 

 while in some of the streaked varieties the structure that has been 

 called Eozoon canadense occurs. In this valley, at Barnaoran, are 

 the famous " Ballynahinch Marble Quarries," from which, in old 

 time, most of the Connemara marble was obtained ; and it was of 

 the stone seen here that Greisecke wrote. Of late years these 

 quarries have got into disrepute, on account of the severe road 

 from them, a steep ridge intervening between Owenglin and Bally- 

 nahinch, over which the blocks had to be carted. This stone was 

 used in the new Museums at Oxford and Trinity College, Dublin. 

 A small vein of a peculiar variety [Onkosin) occurs to the east of 

 Barnaoran ; it is of a pale olive greenish grey colour, full of den- 

 dritic markings, and having an appearance somewhat like moss 

 agate. This, under the name of " moss serpentine," was exten- 

 sively worked by Alick M'Donnell, who discovered it. A very 

 fine specimen is in the Museum, Queen's College, Galway. 



The blocks of stone from this valley have to be drawn across 

 the ridge to the Ballynahinch valley, and from thence to Cloonisle 

 pier for shipment ; they might, however, be manufactured by 

 water power at the quarries. 



Extending southward, at nearly a right angle from the east 

 end of Owenglin, is Glenisky. Here the serpentine occurs in 

 veins that continue southward from those in Owenglin, along the 

 western slopes of Bengower, past the summit of Benlettery, termi- 

 nating on the south slope of the latter. The stones are very similar 



