128 GEOLOGY OF ARRAN. 



and other fossils, alternating with these and with the sand- 

 stones. The whole series dip more to the west and at 

 higher angles, often as great as 70. The total thickness 

 of the beds W. of Millstone Point, as far as the Salt Pans, 

 may be estimated at 5000 feet, of which the limestone and 

 shale make about 150 feet. 



Sandstone and shale with seams of coal succeed these 

 till the beach is obscured by shingle. The principal coal 

 seam is three or four feet thick; but has been worked out, 

 as far at least as the level of the sea, which now invades 

 the workings. It was used only at the adjoining salt and lime 

 works, and never exported. There were workings on two 

 or three seams in the direction of the dip, which is nearly 

 N. at 45; but all were abandoned when, from the 

 depth of the workings, the sea gained access to the pits. 

 The coal is of that variety called blind coed, containing 

 an unusual quantity of carbon, and burning without flame 

 or smoke. Many vegetable impressions, chiefly ferns and 

 calamites, were found in the coal below the shale; the stems 

 of the latter being formed of a hard coal with a bright 

 shining fracture. This character of the coal may be partly 

 due to the action of several dikes which here cut the strata. 

 An adit was opened in the hill above on the strike of the 

 seam, but no coal was found. Still, there seems little doubt 

 that there must be considerable beds of coal yet untouched. 

 The shale and coal tract is bounded by a black limestone 

 below and red limestone above, 1400 yards apart, and 

 extending up against the schist precipices, thus affording 

 ample room for a considerable development of the coal 

 beds. 



A little to the west of this, beyond a shingly beach, sand- 

 stones and shales again appear. The shales contain beds of 

 ironstone, some of which have the structure of septaria; and 

 these, with the variegated shales, form on the shore a flat 

 platform, with a tesselated appearance, like a mosaic pave- 

 ment. " I doubt," says Mr. Headrick (p. 210), " if the most 



