294 DE. C. A. MATLEY ON THE [May I906, 



along them the beds have been pushed southward about 5 feet 

 and 1 foot respectively, the upper thrust having the greater 

 travel. These dislocations have evidently been produced since the 

 decalcification, and they seem to be most easily explained as the 

 effect of the movement of an ice-sheet in Glacial times. 



These black shales, in which cleavage is sometimes still recogniz- 

 able, are correlated by the officers of the Irish Geological Survey with 

 the Black-Shale Series of Loughshinny, but they almost certainly 

 belong to a lower horizon. At Loughshinny a band crowded with 

 Posidonomya Beclieri occurs in the limestones some 70 feet below the 

 Loughshinny Black Shales ; whereas here the uppermost limestones 

 are in the Cyat7ia.vonia-suby.one below the zone of P. Beclieri. 



Dr. G. J. Hinde, E.R.S., has been good enough to examine three 

 slices cut from the chert-bands in this locality ; one from the fresh 

 unaltered chert, one 'from the partly-decalcified beds, and one 

 from the completely-decalcified area. He finds in them various 

 foraminifera (Endotliyra, Noclosinella, Trocliammina, and Val- 

 vulina ?), Calcispliaira (?), sponge-spicules, etc. The specimen of 

 decalcified chert is distinguished by an absence of calcareous material 

 and foraminifera ; and there are certain bodies in it which, although 

 some of them may be cross-sections of sponge-spicules, have more 

 the appearance of casts of simple forms of radiolaria. Dr. Hinde 

 remarks that the chert-slices have a close resemblance to specimens 

 in his possession from the River Hodder. 



The fauna of the CyatJiaxonia-Beds is tabulated in the.faunal 

 lists (p. 297); and from Dr. Vaughan's correlation it appears that, 

 although these beds are represented in the South-Western Province 

 of England and Wales, they correspond more closely, indeed precisely, 

 with the limestones of Park Hill, Thorpe Cloud, etc. of the Midland 

 Province of England. 



(g) Curkeen-Hill Limestone. 



Cnrkeen Hill does not lie on the coast, but is a locality inland, 

 near an old quarry on the road from Rush to Skerries, near 

 Loughshinny. A list of the fauna of its limestone-beds and their 

 correlation are introduced here, because the beds occupy a gap in 

 the Push sequence ; and there was a unique opportunity during the 

 present year (1905) of collecting fossils from them, owing to the 

 lowering of the road at the top of the hill in order to reduce the 

 gradient. The limestone is a rock of a lighter grey colour than 

 the limestones seen at Rush. The Geological Survey-map indicates 

 that the horizon of this limestone lies below that of all the rocks of 

 the Rush section, although Jukes expressed in the Survey-memoir 

 {op. cit. p. 66) his reluctance to accept this view on stratigraphical 

 grounds. That his objection was well founded is now proved by 

 the result of the zonal examination of the fossils, which shows that 

 the Curkeen-Hill Limestone is of Upper Dibunopliyllum-age (D 2 ), 

 though probably older than the Cyathaxonia-TSeds of Rush. 



