2. Alluvial Formations.[1]
At B. Macrevan, in the county of Antrim, half way between Glenevey and Lough Neagh, bituminous wood in disseminated pieces loosely imbedded in a loamy soil has been found.
Two shafts, each sixty feet deep, were formerly sunk to obtain it, but are now abandoned, the stock being exhausted. I however procured some specimens. The wood has evidently retained its fibrous texture, and burns with a vivid flame; specific gravity 1,124.
Not far from B. Macrevan, at B. Vorally, in Sandy Bay, there are still remaining on the shore, a few stumps of bituminized wood, the fissures of which are penetrated by silex, and sometimes even lined by quartz crystals. It does not flame, and its specific gravity, from the quartz it contains, amounts to 2,267.
It was once the general opinion that the waters of the lough had the property of petrifying, and that the quartz contained in the bituminous wood of Sandy Bay had been deposited from them. The experiments however, made by Mr. Tennant during his stay at Belfast, appear to discountenance that belief, since he found no traces of silica whatsoever in the water of the lough.[2]
- ↑ On the shore of Belfast Lough, traces of an ancient forest have been discovered beneath a pest bog. Here a singular phenomenon (first communicated to the Geological Society by Dr. Mac Donnel) occurs, hazel nuts being found, the kernels of which are often converted into calcareous spar, while the shells remain unaltered. I am not aware that the remains of the elk, so common in the alluvial districts of other parts of Ireland, have yet been found in this quarter.
- ↑ As this is the only part of Dr. Berger's notes, in which Lough Neagh is mentioned, I have taken the opportunity of stating some facts concerning it.
Its height above the level of the sea is 132 feet.
Its greatest depth between Arboe and Gartrea points nearly in the contre, 45feet
Its greatest length from north-west to south-east, 19 miles 6 furlongs.
Its superficial contents 97,775 acres.
A constant tradition has prevailed in Ireland, at last since the days of Giraldus Cambrensis, that it owes its origin to some violent convulsion.
The northern and eastern shores of the laugh presents several sandy beaches, in which fine chalcedonic pebbles are found.
