210 
Mr. Weaver on the 
an angle of 32 ° ; whence it seems probable that the trap supports 
the limestone in this quarter also. 
§ 170. In the Kildare range, the hill of Allen (see Plate 6. 
No. 1.) is composed of one great body of granular and compact 
greenstone, and greenstone porphyry, which appear all round the 
base, on the sides, and on the summit, in numerous protuberant 
rocky masses, without any mark of stratification* Some of the 
greenstone is remarkably crystalline, consisting of large crystals of 
hornblende with acicular crystals of felspar. 
Grange hill and the Chair of Kildare constitute in fact one hill, 
with a slight hollow between them. The floetz limestone of the 
latter appears to be disposed in massy strata, four and five feet 
thick, dipping 45° toward the south-east. It is generally greyish 
white, but sometimes mottled, reddish brown being intermixed 
with shades of bluish grey and white ; and it contains bivalves and 
entrochites. In its outgoing to the north-west, the limestone pre- 
sents a rocky face or small escarpment, beyond which is a slight 
hollow, forming the southern foot of Grange hill. In the road 
leading from a farm-house on the other side of this hollow to the 
hill above, the rock which appears at the surface is compact green- 
stone, in some places porphyry tic ; but near the surface it is easily 
frangible, and being much decomposed, acquires almost the appear- 
ance of wacke. Beneath, however, it assumes a greater degree of 
compactness and solidity, and its true character is not to be mis- 
taken. When we consider the dip of the limestone of the Chair 
of Kildare, and the general form of this hill and of Grange hill 
respectively, it seems highly probable that the greenstone is sub- 
jacent to the limestone, and this probability is increased by the 
following fact. The greenstone which I have just described con- 
tains marine exuviae ; and where adjacent to the limestone, it ap- 
