All the other rocks of Antrim are beneath the basaltic beds in geological position. The first is hard chalk, sometimes called white limestone, which does not average more than 200 feet in thickness, and occurs on the eastern and southern sides of the county, and on the southern coast of Rathlin island. The coal district of Ballycastle comprises an extent of about two miles along the coast; the beds crop out above the level of the sea, dipping to the south-east about one foot in nine, and alternate with others of sandstone and slate clay, being themselves of a slaty quality. The only rocks lying under the strata of the great coal district, besides the primitive rocks of mica-slate, &c., already mentioned, are those "of old red sandstone," between the bays of Cushendall and Cushendun. The collieries of Ballycastle, once flourishing, are now but little worked; they were formerly twelve in number, and exported from 10,000 to 15,000 tons annually, Gypsum or alabaster is dug in different places, and the various species of stone are quarried in spots convenient for building and other purposes.
In some places the waters possess medicinal properties, which they are supposed to derive from the adjacent shore. They have also petrifying powers, but these are supposed to exist in the soil, as petrifactions are only found in the lake near the shore of this county, while they are found at considerable heights and depths and at some distance from the coast inland. Valuable hones are made of the petrified wood, and in the white sand on the shore very hard and beautiful stones, known by the name of Lough Neagh pebbles, are found: they are chiefly chalcedony, generally yellow or veined with red, susceptible of a fine polish, and highly valued for seals and necklaces. Besides the fish usually caught in fresh water lakes, Lough Neagh has the char, a species of trout called the dollaghern, and the pullan or fresh water herring. Swans, teal, widgeon, herons, bitterns, and several other kinds of birds frequent its shores. The beds of columnar basalt occur almost exclusively towards the northern extremity of the county, and form an amazing display of natural grandeur along the shore.
Besides the well-known columnar strata composing the Giant's Causeway and the adjacent cliffs, similar strata are seen in divers parts of the county, particularly near Antrim and Kilroot: the pillars com- posing the Giant's Causeway, are irregular prisms standing in the closest contact, and of various forms, from three to nine sides, the hexagonal equalling in number all the rest. Slievemish, or Slemish, mountain is an enormous mass-of greenstone, which likewise occurs in other situations. Porphyry occupies a considerable district to the south of Connor and Kells, and is met with in several other places, particularly near Cushendall. The remarkable substance called wood coal occurs in thin strata at Portnoffer, Kiltymorris, Ballintoy, and elsewhere.
The greater portion being that which surrounds Shane's Castle, and the scattered trees on the steep banks of a few rivers. Numerous, and in some instances extensive, plantations have, however, been made in various parts; and, though there are still many wide naked tracts, there are others well clothed with wood; especially adjoining Lough Neagh, the vicinities of Moneyglass and Drumraymond, the valleys of the Six-mile-water, Kells-water, and the Braid, the whole extent from Lisburn to Carrickfergus, the neighbourhood of Bella hill and Castle Dobbs, of Larne, Glenarm, Benvarden, O'Hara brook, Ballynacre; Leslie hill, and Lisanoure.
The greatest tracts of waste land are the highest portions of the mountain range: even the irreclaimable bogs of these elevated tracts produce a coarse herbage, and many of the bogs which overspread to a considerable extent the plains between the mountains and the Barin are likewise covered with verdure; Towards the southern part of the county most of the bogs have been exhausted. Coal is furnished to the northern and eastern coasts from the mines of Ballycastle, but the chief supply is from England, Wales, and Scotland. The geology of Antrim presents a great variety of the most interesting features, and its mineral productions are of considerable importance. With the exception of a diversified district on the eastern coast and the entire vale of the Lagan, nearly the whole is occupied by basaltic beds, presenting abrupt declivities on the eastern and northern coasts.
There is an extensive salmon fishery along the coast at Carrickarede, between Ballintoy and Kenbane Head, and this fish is also caught at different places along the entire coast north of Glenarm, and also in the rivers Bann and Bush: all the other rivers, except the Lagan, are likewise frequented by salmon; and all abound with eels, which are taken at weirs in the Bann. There is a great variety of other valuable fish off the coast; of testaceous fish this shore affords the lobster and the crab, and oysters of superior size and flavour are found in Carrickfergus bay; the seal is common.
The two largest rivers are the Lagan and the Bann, both of which rise in the county of Down: at Belfast the Lagan spreads into the wide estuary called the bay of Belfast, or Belfast Lough, and above it, with the aid of several cuts, has been made navigable to Lisburn, forming part of the navigation between Belfast and Lough Neagh: the Bann flows through Lough Neagh and Lough Beg, and continues its course to Coleraine, below which it falls into the sea. Most of the rivers strictly belonging to the county rise in the mountains on the coast, and owing to the rapidity and shortness of their currents are unnavigable. The Bush runs westward from the mountains of Lisanoure to Benvarden, and then northward to the sea at Port Ballintrae: the Main flows southward into Lough Neagh, and has three copious tributaries, the Ravel, the Braid, and the Glenwherry: the Six-mile-water also falls into Lough Neagh, at Antrim, and the Camlin, or Crumlin, and Glenavy rivers at Sandy-bay. The rapidity of these and the smaller rivers renders their banks peculiarly advantageous sites for bleach-greens, cotton-mills, and flour and corn-mills, of which the last are especially numerous.
The remains of antiquity of earliest date consist of cairns or barrows, cromlechs, raths or intrenchments, and mounts differing in magnitude and form. The most remarkable of the cairns is that on Colin mountain, about three miles north of Lisburn; there is also one on Slieve True, to the west of Carrickfergus, and two on Colinward. Near Cairngrainey, to the north-east of the old road from Belfast to Templepatrick, is the cromlech most worthy of especial notice: it has several table stones resting on numerous upright ones; and near it is a large mount, also several fortified posts different from all others in the county. There is likewise a large cromlech at Mount Druid, near Ballintoy; another at the northern extremity of Island Magee; and Hole Stone, to the east of the road from Antrim to Glenavy, appears to be a relic of the druids. Of mounts, forts, and intrenchments, there is every variety which exists in Ireland; and so numerous are they, that the parishes of Killead and Muckamore alone contain two hundred and thirty; defended by one or more ramparts; and ten mounts, two of them containing caves, of which that called Donald's Mount is a fine specimen of this kind of earthwork. Among the most remarkable of the rest are, one at Donegore, one at Kilconway, one at the Clough-water, one at Dunethery, the last of which is planted with trees; one with a square outwork at Duumacaltar, in the parish of Culfeightrin; Dunmaul fort, near Nappan; one at Cushendall, having a castle within its defences, and probably a Danish relic; one at Drumfane on the Braid, one at Camlent-Oldchurch, and another in a bog near Ballykennedy: one near ConDor has outworks exactly resembling that at Dromore, and in another near Carrickfergus have been found several curious Danish trumpets. Stone hatchets of various sizes have been discovered in several places, but in the greatest numbers near Ballintoy;arrow heads of flint, spear heads of brass.