Under the name of Lower Shannon is comprehended that par of the river below Limerick which is navigable for sea-going This mstuary is easy of nocess, and its approach is free from danger ; the entrance between the Loop and Kerry Heads is seven miles win and on Loop Head stands a lighthouse, showing a bright fixed light, at the height of 270 feet above high water. About 10 miles to the eastward is a kind of second entrance between Kilkadran and Beal Points, which is contracted to one mile and a half ; and off Beal Point a dangerous sandbank extends nearly half a mile, which still further reduces the navigable channel. On Kilkadran Point is a light house, which exhibits a fixed red light 133 feet above the sea, and inside this point is the small bay of Carrigaholt, which affords good shelter for small vessels. A few miles east from Carrigaholt Bay a landing quay and pier have been formed by the Shannon Commis sioners at Querrin Creek. Above this there is anchorage in every part of the Shannon, though Scattery Island, Tarbert, Labasheda, and Foynes are the only places which offer good shelter from the prevailing westerly winds. On the Clare shore, opposite Scattery, stands the village of Kilrush. [Kii,nusti.] A little above Foynes, on the opposite coast of. Clare, is the new pier of Kilteery, near which are a number of small islands, lying in the western entrance of tho river Fergus, and more than half way up the Shannon towards Limerick. Below this the river presents a different appearance from that above tho confluence of the Fergus; the laud on both sides is high and bold, with a beach either of shingle or gravel beneath, and the channel is free from dangers; whilst above this point the laud is so flat and low, that, with little exception, the whole shore on each side is one continued line of embankment. For eight or nine miles below Limerick the river is so shallow, that at low water every vessel must lie aground ' • but the channel has been recently improved by the removal of shoals and rocks, and has been carefully marked out by beacons.
.At Limerick a very fine range of quays has been constructed, and a weir has been formed across the river below the town, with a lock to admit vessels at high water, so as to constitute a floating dock of the whole river above the weir.
Several rivers join the Lower Shannon, among which the Fergus deserves some notice, as it is navigable for vessels of 200 to 250 tons at high water as far as Clare, 9 miles from the Shannon, where a landing-wharf has been built by the Shannon Commissioners. About 9 miles below Limerick the Maigue falls into the Shannon on tho Limerick side; though narrow, it is free from obstructions, except a rocky bar across the entrance, and is freely navigable for boats of 40 or 50 tons deeply laden as far as Adore, about 8 miles from its mouth. There are numerous other streams, many nearly dry nt low water, though accessible at high water.
The spring-tides in the Shannon rise from 17 to 18 feet, the neap tides about 14 feet; the velocity, which at the mouth does not exceed a mile an hour, increases as the river becomes narrower to upwards of three miles during the ebb at spring-tides ; in consequence of which the young flood has so much resistance to overcome, that when it does so it rushes up almost like a bore, and the water rises during the first hour's flood as much as seven or eight feet, by which time a great portion of the mud-banks become covered, and from having a more expanded space to vent itself in, tho velocity diminishes.
The improvements of the Shannon, which were begun by grants from the Irish Parliament and continued by the Directors-General of Inland Navigation, were in 1839 placed under the direction of com missioners, appointed under the Act 2 & 3 Vict., c. 61. The cost of the works was upwards of half a million of pounds sterling. The control of the navigation was transferred to the Board of Publie Works. The navigation is opened for traffic throughout its whole length, from the upper extremity of Lough Allen to the city of Limerick, a distance of 143 miles, forming with the Boyle and Strokes town branches a river and canal communication of 158 miles, of which 129 miles are adapted to the navigation of large steamers.