118 MR. GARDINER AND PROP. REYNOLDS ON THE [May 1909, 



following fossils were found: — Cheirurus sp., Orthis testudinaria, 

 Dalm., Orthis sp., Plectamhonites sericea, Sow. (?), Leptcena cf. llaa- 

 deiloensis, Dav., and Aerotreta (?) hibzrnica, sp. nov. 



A patch of limestone-breccia and a mass of compact limestone 

 occur in association with these rocks, the compact limestone being 

 bounded on the west by a mass of coarse breccia which probably 

 represents a vent. To this we shall refer subsequently. 



(4) The district lying north-west of Shangort. — 

 A strip of Llandeilo ashy rocks, overlapped on the west by the 

 coarse (?) Bala conglomerate, extends in a north-easterly direction 

 from Stream H to Derrindaffderg, a distance of about three-quarters 

 of a mile ; and a second strip, separated from the first (except at 

 the northern end) by a long tongue of red felsite, lies farther 

 east. The ashy series met with in this region does not include 

 examples of the gritty beds which have yielded fossils on the south, 

 but consists entirely of definite tuffs, which sometimes, especially 

 in the southern part near Stream H, are very coarse. The felsite 

 that separates the two strips of tuff sometimes contains xenoliths ; 

 and it is by no means easy to discriminate in the field between 

 it and some of the tuffs. 



(b. 2 ) The Calcareous Series (Tourmakeady Beds). 



Along the western side of the area, from a point about 300 yards 

 north-east of Tourmakeady Lodge to Gortbunacullin Farm bridge, 

 are numerous exposures in a very remarkable deposit of a calcareous 

 nature. As will be seen by reference to the map (PI. IV), the deposit 

 is far from being continuous ; at certain places it has obviously been 

 broken up by earth-movements, but there seems no reason to 

 suppose that the bed originally formed a continuous deposit between 

 the various spots where it is now found. 



The calcareous rocks show three different lithological types : — 



(1) Compact bedded limestone. — This is rarely seen. 



(2) Limestone brecciated in place. — This is only occasionally met 



with, the commonest type of calcareous deposit being 



(3) Limestone-breccia; and if this is, as we believe, a deposit produced 



by volcanic explosions, it is easy to understand how it might be formed 

 in disconnected patches on the floor of the sea near the vent or vents 

 through which it was ejected. 



Some further details regarding these three types of calcareous 

 deposit may now be given : — 



(1) Compact bedded limestone. — This is red, pink, or grey 

 in colour, and contains in some places quartz-grains which near 

 Shangort become so numerous that the rock passes into a calcareous 

 sandstone. 



(2) Limestone brecciated in place. — This is apink or white 

 rock, which, after being cracked into numberless pieces, has been 



