116 



THE GEOLOGIST. 



open from above, and in all cases a tunnel which communicates with the beach 

 below. The tunnel, probably, was formerly the cave, the top or ceiling of 

 which giving way, produced the curious tunnel-shaped appearance as seen from 

 above. There are several of these ; one near Sorel, in Jersey, called " Le creux 

 du vis," and two in Sark, called "Le creux terrible," and " Le Pot," being among 

 the most remarkable. There are many other ordinary shaped caves in all the 

 islands, produced both by the action of the sea on the softer strata, and by the 

 first great upheaval which raised these islands from the ocean. — J. H. Mac- 

 allister, Stoke Goldington. 



Drift at Donald's Hill, Ireland. — Dear Sir, — As any fact which eluci- 

 dates the occurrence of osseous remains in what is called " The Drift," and the 

 probable age or history of that deposit as determined by such collateral evidence, 

 is at present of especial interest to geologists, the accompanying sketch and 

 remarks, taken from one of my note books, wi 1 !, I am sure, interest you. 



Surface, with soil. 



Quarry in Chalk, or "White Limestone," at the base of the Basalt, 700 feet above the sea. 

 South flank of Donald's Hill, townland of Kilhoyle, co. Deny : (sheet 17, Ord. map). 



1, Drift clay, formed by the disintegration of the basalt. 



2, Basalt compact at top, becoming soft and earthy below, and resembling a variegated 



shaly sandstone. 



8 ' ' l: "t'lu ' hiii?) lk " mUd ' containilI S sub-angular lumps of red and grey (chalk-drift, below 

 £ | •^V^rMMi,' 1 ' 1 ,lnitS ' hardeued to a compact limestone with conchoidal fracture. 

 A A, Base line of recent drift. 



B B, Hollows in the surface of the chalk, containing fragments of deer's horns and bones. 



On the southern Hanks of Donald's Hill, county of Derry, town-land of 

 Killiovh', and al an elevation of seven hundred feet above the sea, a large quarry 

 ma opened many years -back, in the hard, or as it is called by geologists, 



• altered chalk, known locally as « white limestone," at the very limit of the 

 escarpment oi superincumbent basalt which covers the entire remaining upper 

 Porta oj the mountain. The chalk, which, as usual in the counties of Derry 

 and \„t nm, resembles a close-rained compact white marble, with a conchoidal 

 fracture is here, as elsewhere, overlaid by a stratum of drifted sub-angular 



ml slungle, enclosed in what was once chalk mud; but which is now nearly as 

 hard as the chalk itself. On this ancient chalk-drift the basalt rests-the junc- 



