346 Proceedings of the Royal Irish Academy. 



What I, therefore, now put forward in respect to the Cambrian 

 age of the rocks now in question is only conjectural. It would 

 appear to me that they are a portion of the rocks which occur in the 

 hills called Benbo and Slieveslish, south and eastward of Lough Gill, 

 Co. Sligo. These latter rocks are very similar to some of the lower 

 rocks in the West Galway section ; rocks which, us shown in former 

 Papers read before the Academy and elsewhere, are probably Upper 

 Cambrians below the passage beds between the Cambrian and Cambro- 

 8ilurian formations. 



