O. H. Kinalian — Iri%li Silurian Land Plants. 399 



Salter, and. Jukes. The first two were inclined to place the Dingle 

 and Glengariff rocks among the Silurians, while the other two 

 objected on account of the fossils, — eventually it was arranged that 

 they were to be joined provisionally to the Old Eed Sandstone 

 under the names of Dingle beds and Glengariff grits, until the 

 somewhat similar rocks in Connaught and Ulster were examined. 

 Afterwards, Jukes, although be did not separate the Glengariff 

 grits from the Old Eed Sandstone, gave the Dingle beds a distinct 

 grouping; but Du Noyer, and all the other officers who were en- 

 gaged in the examination of the country, considered that the Dingle 

 beds and Glengariff grits were of one age. During Jukes's life- 

 time, these rocks were being gradually worked out ; but after his 

 death seemingly they have been forgotten. 



The Louisburgh beds, although no fossils have been found in them, 

 except some Annelid burrows and obscure markings, are in part 

 similar to the fossiliferous Salrock beds, and in part like the fossil- 

 iferous Mweelrea beds; they probably are the newest group of the 

 Silurians in Mayo. The Croaghmoyle conglomerates seem to be 

 capped unconformably by Carboniferous rocks ; they are like the 

 Toormakeedy conglomerates, associated with which Upper Llan- 

 dovery fossils occur; also the limestones that occur in the Toor- 

 makeedy rocks seem to occur in places at the margin of Croaghmoyle 

 conglomerates. In red beds associated with, the Croaghmoyle 

 conglomerates I detected obscure markings that possibly might be 

 fucoids, but they were so very indistinct that no reliance could, be 

 placed on them. 



The Lough Gara rocks were suspected by Griffith to be simi- 

 larly placed to the rocks at Dingle ; that is, to lie conformably on 

 the Silurians, while they were capped unconformably by Old Eed 

 Sandstone (Lower Carboniferous Sandstone). When I visited 

 them with Foote, that observer seemed inclined to class them with, 

 the Dingle beds, but unfortunately he did not live to complete 

 his examination. In the Government Survey Memoirs, Ex. Sheet 

 76, page 7, Berdoc Wilkin says of these rocks near Ballyhaderreen, 

 " They appear to be conformable with the Silurian beds, but are 



overlapped unconformably by the Lower Carboniferous 



Sandstones " ; this observer coming to the same conclusion as that 

 suggested by Griffith and Foote. Foote suspected that fossil plants 

 occurred in these rocks. 



The Fintona and Slievemore rocks are very similar to those in the 

 Curlew Mountains, and are capped unconformably by the Old Eed 

 Sandstone (Lower Carboniferous Sandstone). Portlock states that 

 they seem to pass conformably into the underlying Cambro- Silurian 

 rocks, which would make them of great age ; but Griffith suggested 

 that they were of the same age as the Dingle beds. The Dingle, 

 the Mweelrea, the Toormakeedy, the Curlew Mountain, and the 

 Fintona rocks have conditions in common : all are unconformable 

 with the overlying Lower Carboniferous Sandstone (Old Eed Sand- 

 stone) ; all have similarly associated basic felstones (Eurytes) and 

 tuffs ; and all, except the Fintona rocks, lie conformably on rocks 

 containing typical Silurian fossils. 



