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sometimes grey ; always hard. One runs m a south-east direction 

 across the entrance to the excavation. It is on the west side 18 feet 

 wide at the top, and 30 feet lower down it is only 3 feet. Another 

 appears by its direction to cut this at right angles. It is 6 yards thick, 

 and is a mixture of trap, flints, pieces of chalk, and red sandstone, all 

 cemented into a very hard solid mass, trap and flints predominating. 



I have just stated that there is no trap overlying the chalk at 

 Moira, as it does in general; there are about 18 square miles of the 

 county in this condition in the vicinity of Moira, Lurgan, and Porta- 

 down, outside the south end of the trap district. 



2. Ballynalargy, or Balmer's Glen, is about two miles north-east of 

 No. 1. At this quarry about 50 feet in thickness of the limestone is 

 visible, but it has not been quarried to the bottom, and it may be 20 feet 

 or more lower than the bottom of the present excavation, or 70 feet in all. 

 The rock here dips west 5°. A whin dyke, about 5 feet wide, runs across 

 at the entrance of this quarry, and continues in the same way through 

 another, which lies a few perches to the south of this one. This dyke 

 has been noted of old for yielding fuller's earth, part of which was 

 carried to Dublin for economic use. This fuller's earth is decomposed 

 trap. Some of the whin dykes are of very hard trap — some so soft that 

 they could be shovelled away as easily as sand. Some of it is like 

 snuff in colour, and between the fingers the fuller's earth at Balmer's 

 Glen is of this brown impalpable dust. The dyke in which it occurs is 

 divided vertically into irregular lenticular masses, red, yellow, brown, 

 or black, soft or hard. This dyke is soft at the sides, but in the middle 

 it has " a heart as hard as any wheenstone." 



In all places where the chalk is exposed, from the trap having been 

 removed, the top of it is worn into holes, as if by the action of 

 water. Those holes are from 3 to 1 2 inches in diameter, and about 

 half as deep ; they are often filled with rounded flints, from three to four 

 inches in diameter, mostly of a red colour, but a few are gray. There is 

 a bed of red impalpable clay immediately over the chalk, and between 

 it and the lower bed of trap, which buries or encloses most of the flint 

 pebbles. The red clay bed seldom exceeds two feet thick, but it is 

 variable. Near Belfast it is from one to two feet thick. Col. Portlock 

 says he found it 13 feet thick at Magilligan. 



The chalk has not been made crystalline at the top, where it 

 underlies the trap, and is nearly in contact with it, as we see it where 

 it comes in contact with whin dykes. The reason of this appears to be, 

 that though the trap might have been emptied in a semifluid state, the 

 bed of red clay just mentioned, when wet, or even if nearly dry, would 

 protect the chalk from the effect of the overlying red hot trap, until it 

 became cool, which the first single layer would soon do in the bottom 

 of an ocean. In making castings of iron, the red hot metal does not 

 alter the moist sand of the mould into which it is poured. 



The late Dr. Mac Donnell, of Belfast, was the first who noticed and 

 told to others that the top of the chalk was not altered where it came 

 into contact with the trap, as he had observed it to be, in junction with 



