498 Proceedings of the Royal Irish Academy. 



Creggaunlaun. — In the greater part of this area the rocks are 

 metamorphosed. Those that are unaltered are of the " grey and 

 green " type, and yield fossils of Wenlock and Upper Llandovery 

 types. They lie tinconformably partly on metamorphosed and partly 

 on unaltered Cambro- Silurians. 



Mweelrea Mountains. — The rocks here are partly of the " Eed 

 arenaceous" type and partly of the " grey and green" type : the two 

 types in places are intermingled. In some of the grey and green 

 beds there are fossils principally of the Caradoc-Bala species. They 

 lie unconformably on metamorphosed and unaltered Cambro-Silu- 

 rians. 



Formnamore Mountains. — These rocks, although on the same geo- 

 logical horizon as those of the !Mweelrea Mountains, are, for the most 

 part, of the " grey and green" type, but no fossils hare been found in 

 them. They lie unconformably on metamorphosed Cambro-Silurians, 

 and are capped by Carboniferous rocks. 



Toormaheady Mountains. — Here a second change takes place ; the 

 rocks, although a continuation of the last, being nearly altogether 

 massive red conglomerates ; but at their base are limestones and tuffs, 

 carrying fossils of Caradoc-Bala types. They lie unconformably on 

 metamorphosed and unaltered Cambro-Silurians ; while, like the rocks 

 of the Formnamore Mountains, the Carboniferous rocks lie uncon- 

 formably on them. 



Tract of Country letween Cong, Lough Corril, and the Culfin, on 

 the Atlantic. — The rocks here are separated from those of Mweelrea, 

 Formnamore, and Toormakeady, by a great nearly E. and "W. fault, 

 with a downthrow to the southwards. They are nearly altogether of 

 the " grey and green" type, but with them are associated remarkable 

 subordinate sets of beds of the "red arenaceous" type. The upper- 

 most beds, " Salroek slates," belong to the latter, and have, as theii' 

 characteristic fossil, one of an Upper Llandovery type ; while lower 

 down various types of fossils are intermingled — one zone carrying 

 fossils of Caradoc-Bala species. These rocks lie unconformably on 

 metamorphosed rocks of Cambro-Silurian and Cambrian ages, while 

 they are covered unconformably by the Carboniferous rocks. 



Dingle Promontory . — The rocks (Anascaid beds) that are sup- 

 posed to be the oldest in this district contain Cai'adoc-Bala species. 

 Jukes and Du IS'oyer classed them as Silurians, while Griffith and 

 M'^Henry would put them among the Cambro-Silurians. Of the rocks 

 forming a continuous sequence, the lowest (Smerivick beds) and the 

 highest {Dingle beds) are of the "red arenaceous" type; the rocks in 

 the intermediate groups are of mixed types, the " grey and green" type 

 predominating. The base of the rocks of the sequence is not seen ; 

 while on the Dingle beds the Carboniferous rocks lie unconformably. 



Glengariff Grits. — These rocks are principally of the "red arena- 

 ceous" type; theii' base is not exposed; while on them the Carboni- 

 ferous rocks rest conformably in the country to the southward (West 



