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Proceedings of the Royal Irish Academy. 



collected on the flanks of Mweelrea {Meoulrea). This mountain, 

 ascending from the north shores of Killary Harbour, is nevertheless 

 shown on the published maps as consisting of Wenlock strata. Only 

 the topmost beds seem to hold so high a place in the Silurian group 

 as Llandovery. 



2. Strata south of Leenane considered to be Llandovery were 

 represented as passing directly up into the Ludlow division, the 

 Wenlock series being entirely omitted ; though this was believed to 

 exist in force as we have just seen in Mweelrea, that is, in the 

 immediate vicinity. 



3. A well-marked series containing Brachiopods and turbinated 

 corals, and in a few places Pentamerus Knightii, was relegated in 

 parts to the "Wenlock and in parts to the Llandovery group. 



4. A volcanic zone with fossil-bearing ash of Caradoc or Bala Age, 

 and grits also containing fossils of this age, was represented as having 

 been faulted up near Toormakeady amongst Llandovery strata ; 

 although the succession seems obvious and unbroken.^ 



Such instances are sufficient to indicate the necessity for a revision 

 of the published work ; and a rapid re-survey of the ground was 

 planned by the late Director-General, Sir Archibald Geikie, and 

 allotted to me. The re-examination, though limited in time for 

 so large a tract, brought to light several new points of evidence, 

 the chief of which may here be summarized, following those previously 

 mentioned, in numerical order : — 



5. The coral-zone mentioned above occurs in the ground represented 

 as mica-schist — Metamorphosed Lower Silui'ian " — 2^ miles south- 

 west of Croagh Patrick summit.^ 



6. Beds of the same zone, very slightly altered, which yielded to 

 me specimens of a turbinated coral, now in the Museum Survey 

 collection, appear half a mile west of Croagh Patrick summit, 

 brought up between two limbs of the associated quartzite (see p. 158) 



7. This zone, known to exist near Lough Mask, was traced west- 

 ward by Maam to the coast near Kyleraore ; and, occurring 

 as it does near the base of a great grit series, justifies the change of 



1 From Llandeilo or Arenig grit and coarse, massive conglomerate, through 

 associated block slate, into overlying felsite, calcareous ashes with Bala fossils and 

 limestone beds. The felsite may perhaps lie unconformably upon the black slate. 



2 At Boheh. During a recent visit to this locality with the present Director 

 of the Survey, Professor Cole, some newly quarried flags yielded Pentamerus and 

 other forms. 



