Vol. 62.] CARBONIFEROUS ROCKS AT RUSH. 289 



(d) The Carlyan Limestones. 



These beds are separated from those last described by the entrance 

 to Eush Harbour ; and, although a gap of only 200 feet divides the 

 two series, there is a marked difference in the lie of the beds. On the 

 south side of the harbour, the Upper Eush Slates, the Conglomerate- 

 Group, and the Supra-Conglomerate Limestones have been dipping 

 steadily at angles of 50° to 65° ; while on the north side the 

 Carlyan Beds undulate at low angles, though with a general 

 northerly dip. From this marked change of dip, and from the fact 

 that the numerous small faults seen on the south side of the 

 harbour are not traceable across the harbour-entrance, and that 

 there is some disturbance of the beds, seaward, on the north side, 

 it seems probable that there is a strike-fault here, though of no 

 great throw, as the two sets of rocks correspond closely in lithological 

 character. If there is no fault, the top of the Supra-Conglomerate 

 Limestones is about 100 feet below the horizon of the Carlyan 

 Beds. 



The latter consist of dark-grey, well-bedded limestone, and dark 

 calcareous and argillaceous flaggy beds, which at several horizons 

 are charged with numerous small fragments of slate and other rocks. 

 They are quarried locally for building-purposes. They occupy a 

 low rocky shore covered at high tide, and disappear northwards 

 under the waters of Eush Bay at an angle of 15° to 20°, after 

 exposing about 180 feet of beds. 



Fossils are by no means abundant, and the few that have been 

 collected are unsatisfactory for zonal purposes. They probably 

 belong, either to the Lower, or to the Upper Seminula-Zone. 



(e) The Kate Rocks. 



These are low weed-covered rocks, projecting from the sands of 

 Eush Bay, and are only accessible at low tide. They are separated 

 from the Carlyan Eocks on the south by 300 yards of sandy beach, 

 and by nearly the same distance from the Cyathavonia-Beds on the 

 north. They comprise a set of thickly -bedded limestones, underlain 

 and overlain by thin, laminated, black, calcareous shales and thin 

 limestones. They contain moreover some chert-seams, and rock- 

 fragments have also been found in the limestone. 



These beds are disposed in a rapid succession of sharp folds, 

 which are often slightly overfolded, with the crests of the anticlines 

 turned towards the north. Fig. 8 (p. 290) shows a section across 

 these beds. Owing to the complicated structure, the exact thickness 

 of the beds has not been ascertained; but probably about 90 or 100 

 feet are exposed, of which some 15 feet would consist of the thick 

 beds. 



At present, fossil evidence is too meagre to allow of these beds 

 being correlated precisely. They are, in all probability, intermediate 

 in age between the Carlyan Limestones and the Gijat7iacco)iia-Beda 

 now to be described. Their occasionally-included rock-fragments 

 connect them with the former, and their chert-seams with the latter. 



