116 
THE GEOLOGIST. 
open from above, and in all cases a tunnel wWcli communicates with tlie beacli 
below The tunnel, probablv, was formerly the cave, the top or ceihng of 
which ffiviii'^ way, produced the cuiious tunnel-shaped appearance as seen from 
above The'i-e are several of these ; one near Sorel, in Jersey, called " Le creux 
du vi'''" and two in Sark, caUed "Le creux temble," and " Le Pot," bemg among 
the most remarkable. There are many other ordmary shaped caves m all the 
islands, produced both by the action of the sea on the softer strata, and by the 
lirst ffreat upheaval which raised these islands from the ocean.— J. H. ;Mac- 
allis'ter, Stoke Goldington. r ^ -u- i, i • 
Drift at Donald's Hill, Irelai^d.— Deah 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 preseiit of especial interest to geologists, the accompanying sketch and 
remarks, taken from one of my note books, wi'l, 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, tovrnland 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. 
3, Hardened chalk-mud, containing sub-angular lumps of red and grey (chalk-drift, below 
the basalt). 
4, Upper chalk with flints, hardened to a compact limestone with conchoidal fracture. 
5, Layers of flint. 
A A, Base line of recent drift. 
B B, HoUows ia the surface of the chalk, containing fragments of deer's horns and bones. 
On the southern flanks of Donald's Hill, county of Derry, town-land of 
Kilhoyle, and at an elevation of seven hundred feet above the sea, a large quarry 
was 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 of superincumbent basalt which covers the entire remaining upper 
portion of the movaitain. The chalk, which, as usual in the counties of Derry 
and Antrun, resembles a close-grained compact white marble, with a conchoidal 
fracture — is here, as elsewhere, overlaid by a stratum of drifted sub-angular 
flint sliingle, enclosed in what was once chalk mud ; but which is now nearly as 
hard as the chalk itself. On this ancient chalk -drift the basdt rests — the June- 
