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The bedding, so far as it can be tested in shallow work- 

 ings, is approximately level, and the dip, when present, is 

 slight, various, and local. It is the most characteristic form- 

 ation on high ground throughout the district, but is recog- 

 nized chiefly by angular stones scattered over the surface 

 of the ground. It forms the principal building stone of the 

 neighbourhood, but the quarries from which it is won are 

 level with the ground. Its material undoubtedly represents 

 the waste of the coarse pegmatites which form the dominant 

 rocks of the crystalline series of the district. 



The following outcrops, among others, were noted: — 



1. Durham's Quarry (pi. xix.). Situated within 2 miles 

 of Ardrossan, towards the north-west angle of Section 77, 

 behind Mr. Dinham's house. The stone is worked in two 

 quarries that are parallel to each other, each quarry having 

 a face of about 8 feet in height, with the stone dipping into 

 the hill. The dip is south 10° east, at about 15°. The outerop 

 can be traced along the foot of the hill for at least half a 

 mile to the westward of the quarries, where it passes into 

 scrub country and is replaced by reddish sand, which is pro- 

 bably the decomposed remnants of the same rock. About 

 one-eighth of a mile to the west of Dinham's quarries a small 

 exposure of the rock is seen in a trial pit, and here the beds 

 are apparently level. 



The rock is bedded but differs greatly in the size of grain 

 within short distances, from a fine siliceous sandstone to small 

 gravel. The stone is much jointed, but no quartz veins were 

 noticed. A thin slate-band occurs in one part of the quarry. 

 Near the eastern end of the southern quarry there is a 

 brecciated dyke which penetrates the bedding at right angles, 

 caused by two parallel faults with displacement between the 

 walls, which are smooth, and the pseudo-dyke is made up of 

 broken fragments of the bed rock cemented together. The 

 dyke has a thickness of 18 inches near the top, but widens in 

 its downward extension. The quarrymen have left this dyke 

 standing whilst removing the stone from either side, so that 

 it projects 9 feet from the face of the wall of the quarry, and 

 can be traced at surface for a distance of 32 yards. 



On the northern side of the quarries the igneous and 

 schistose rocks of the Pre-Cambrian, with discordant dip and 

 strike, are seen to outcrop and come close up to the grits, 

 the angular fragments of each class of rock blending in great 

 number's at the line of junction, but the intrusive rocks do 

 not penetrate the grits. The rise at the back of the quarries 

 is covered by fossiliferous Miocene cherts and travertine. The 

 Cambrian limestones outcrop in a position H miles to the 



