It is worthy of remark that the surface of both the estuarine clay, and the re-assorted Boulder clay maintained an exactly uniform level over the whole of the excavations.

The surface clays consisted of blackish clayey and sandy layers, with abundance of Mya arenaria, Cardium edule, Tellina balthica, Mytilus edulis, and were still in course of deposition.

The yellow sand contained a large variety of species, some of them, such as Thracia, Lucinopsis, and Scrobicularia, evidently derived from the washing down of the older beds. The upper estuarine clay had all the characters already described-very fine, tough, and unctuous; it yielded abundance of Pecten maximus, Cardium echinatum, Lucinopsis undata, Thracia convexa, Scrobicularia alba, Aporrhaïs pes-pelecani, Nassa pygmæa, Scalaria turtonæ, all of fine size. Between the upper and lower clay was a zone characterized by Pholades, the occurrence of which was also noticed by Stewart in his investigations on the opposite side of the Lagan, and, as he points out, is the first indication of the subsidence which resulted in the deposition of the upper clay. Three species occur-P. crispata, P. candida, and P. dactylus; the shells all still in the natural vertical position. The enormous size which the first-named reached has been noticed by several writers, and is referred to on another page of the present Report. The lower clay is also typical, but contains a richer fauna than usual, as shown in the writer's Paper in Proc. B. N. F. C., but its most abundant fossils are still Cardium edule, Tapes decussatus, Tellina balthica, Scrobicularia piperata. The gray sands above and below the peat-bed are marine, as shown by the presence of Foraminifera. The peat is here twenty-eight feet below high-water mark; it yields the usual plants, and also bones of the red deer and wild boar. The red sand yielded a very few Foraminifera only.

(9). West Bank.—The West Bank lies in the middle of the lough, three miles below Queen's Bridge, Belfast. In the work of forming the new Victoria Channel, which has replaced the former tortuous approach to the harbour, this bank has been cut through for a length of over a half a mile, and to a depth of some 30 feet. Throughout this length and depth the material was solid estuarine clay of the Thracia zone. By the kindness of Mr. W. A. Currie, Secretary to the Belfast Harbour Commissioners, I was able to visit the works, and to select samples of clay from all depths, as brought up by the large steam dredgers engaged on the excavation. 15 lb. samples were taken from depths of 12, 17, 24, and 32 feet below the surface of the bank, which is four feet below high-water mark. From top to bottom the deposit

was typical upper clay, and, as might be expected from its distance from land, was unusually fine and pure. Fossils were rarer than is usual in the Thracia clay, but were in large variety, and all the characteristic upper clay fossils were present. The clay from 12 feet below surface was of more littoral character than that from greater depths. In the 17 feet samples, Pholas candida occurred in great profusion. In the lower two samples, shells were few, and Foraminifera almost absent. Nucula nucleus, Cardium exiguum, Lucinopsis undata, Scrobicularia alba, Turritella terebra, all characteristic upper clay fossils, were present in every sample. The captain of the dredger informed me that at one point a browner clay, with more shells, was touched. This was probably the Scrobicularia or lower clay, which must here be some 35 feet below high-water mark. Foraminifera occurred but sparingly in all the

samples obtained at West Bank.

(10). Holywood.—The flint implement-bearing gravels of the Kinnegar, at Holywood, rest on estuarine clay. Its depth is not known, but I am informed by Mr. W. Nimick, builder, of Holywood, that during the construction of the gas-works there in 1860, excavations 22 feet deep were made in the clay, large oyster-shells being found down to the bottom, and piles driven for the foundation of the chimney went down 38 feet before reaching firm ground. A little to the eastward, at the old pier, the New Red Sandstone was struck eight feet below the surface. Further eastward, at the mouth of a stream which passes Seapark-terrace, the submerged peat may be seen on the shore between tides, filling a shallow trough in the Boulder clay, which crops out all round. It is two feet in thickness, full of trunks and branches of Scotch fir especially, but also of willow, oak, and hazel, and marsh plants; one log of oak measured 25 feet in length by five feet in circumference; excellent impressions of willow leaves, apparently Salix aurita, were noticed, and hazel nuts. The peat rests on one foot of fine red sand, which rests in turn on Boulder clay. No estuarine clay was here observed; the peat may be seen also in the banks of the stream, where it is about 6 feet above high-water mark, and underlies some feet of stratified gravel (raised beach). On the beach, a couple of hundred yards further eastward, the Bunter sandstones crop out. The estuarine deposit continues westward of the Kinnegar, but at Tillysburn the underlying beds again rise to the surface. Large trunks of oak were formerly dug out of the shore near the latter place, and sawn up for use as timber; they evidently came from the submerged peat, since the red sand which underlies it appears on the shore a little further on. I took samples of estuarine clay at the Kinnegar from a depth of four

feet below the surface. The deposit proved poor in fossils, and apparently is a surface clay containing some shells washed out of the Thracia zone, or else the upper surface of the deep-water clay with littoral shells lying on it. Foraminifera occur very sparingly.

A few other sections of the beds in the Belfast estuary have been described, and are available for comparison. At Spencer Basin the excavations, over 20 feet in depth, were through estuarine clay only, the surface beds, Thracia clay and Scrobicularia clay, being all well shown.1

In Smith's "Outlines of the Rocks of Antrim," p. 123 (Belfast, 1868), after a brief general description of the Belfast estuarine beds, four sections are given, the result of trial pits sunk into the dock bottom when the construction of Spencer Basin was in progress. The sections are from 38 to 54 feet in depth, and show a series of strata, closely resembling that at Alexandra Dock, already described. Underneath from 23 to 32 feet of blue clay, is a bed of peat, varying in thickness from 8 inches to 3 feet, a bed of gray sand being in some cases interposed, while where the peat was thinnest it underlay 8ft. 6in. of "vegetable loam, approximating to peat." Below the peat was a gray sand (0 to 2 feet); then dark red sand (4 to 6 feet); and under this, alternating layers of red clay and red sand, belonging to the Boulder clay series. At King-street, Belfast, the following succession of beds was passed through in sinking a well

1. Estuarine clay of the usual yellowish gray colour;
Foraminifera rather common,

2. Estuarine clay of brownish colour, and with offensive
smell; Foraminifera very common,

3. Fine sand; Foraminifera rare,

4. Very fine Boulder clay; Foraminifera very rare,
5. Boulder clay, as it usually occurs in our neighbour-
hood; Foraminifera plentiful, .

6. New Red Sandstone.

The surface here was a few feet above high water.

Feet.

6

22

24

50

100

202

A layer of twigs and hazel nuts at the base of bed No. 2 evidently represented the submerged peat.

In sinking for a well at Police-square, Belfast, the beds met with were1:

7

Gravel charged with water, and containing a quantity of

organic debris,

Very tenacious clay, "a thick deposit."

40

These gravels, lying between the estuarine clay and Boulder clay, probably correspond to the peat and gray sands of Alexandra Dock. The most interesting point about them was that they here yielded an inflammable gas, which, when an iron pipe was sunk, "flowed freely at the rate of 40 cubic inches per minute through the upper end of the pipe, and, when ignited, burned with a yellow flame, which could scarcely be distinguished from ordinary coal gas."

A careful analysis showed the following composition :—

"From this analysis," says Professor Andrews, "it is evident that the gas formed in this subterranean sheet of water is, in all respects, the same as that which is produced in stagnant pools containing leaves and other vegetable matters."

At Sydenham railway station, a mile east of Alexandra Dock, the Boulder clay has risen, and the section is:

:

The surface of the estuarine clay here is three feet above highwater mark.

'Prof. Andrews, in Proc. Belfast Nat. Hist. and Phil. Society, 1873-74, p. 93.

V. STRANGFORD LOUGH.

In Strangford Lough there is no large area of estuarine deposits as in Lough Foyle and Belfast Lough, but several isolated patches of some interest occur. The extensive flats which extend from Newtownards to the water, and the miles of Zostera banks which are laid bare at the upper extremity of the lough, and the low grounds fringing the estuary of the Comber River, have everywhere a substratum of the Post-glacial red sands before mentioned, or of Boulder clay, excepting one or two shallow patches of sandy estuarine clay laid down in the hollows which streams have formed. It is probable that estuarine clays of some depth underlie the slob lands that extend among the islands about Ardmillan and Killinchy, and clays there visible at low water look very like the surface of a deep deposit, but no sections are exposed.

(1). Newtownards.-Samples of sandy clay were obtained at about high-water mark near the sluice-gates on the Greyabbey road, a mile from Newtownards, and again on the eastern shore of the lough a mile below this place. The two samples were very similar in fauna, being rich in small shells, some of which, like Montacuta bidentata, M. ferruginosa, Caecum glabrum, Jeffreysia opalina, Rissoa albella have not been taken in a recent state in the lough; the last-named is present in the clay in the greatest abundance. The deposit yields shells characteristic of both the upper and lower zones, and like the neighbouring deposit at Kircubbin, to be next described, appears intermediate in character. Foraminifera were not abundant.

1

(12). Kircubbin.--The occurrence of estuarine clay at Blackstaff Bridge, two miles south of Kircubbin, on the eastern shore of Strangford Lough, was first observed by William Gray, as stated in Wright's Paper, in which forty-two species of Foraminifera are recorded from this bed-the only published notice of it. The clay occurs in a shallow basin among low hills of Boulder clay, near the margin of the lough, and is seen in the banks and bed of the Blackstaff, a small and sluggish stream. Under three or four feet of horizontal bands of brown, loamy, and gravelly strata-fresh-water beds— is a deposit of estuarine clay of the usual character. The upper surface is slightly above high-water mark, and the clay is at least three feet

1 See Dickie, "Report on the Marine Zoology of Strangford Lough,” Report of British Association, 1857.