20 THE OLD RED SANDSTONE. 
breaches towards the south; but it stretches, almost without 
interruption, for about a hundred miles, from the near neigh- 
borhood of Cape Wrath to the southern extremity of Apple- 
cross; and though greatly disturbed and overflown by the 
traps of the inner Hebrides, it can be traced by occasional 
patches on towards the southern bar. It appears on the 
northern shore of Loch Alsh, on the eastern shore of Loch 
Eichart, on the southern shore of Loch Eijl, on the coast 
and islands near Oban, and on the east coast of Arran. De- 
tached hills and island-like patches of the same formation 
occur in several parts of the interior, far within the frame or 
Milne, Low, and Co., Woolmanhill. The bore is 8 inches in diame- 
ter, and 250 feet 9 inches deep. It required nearly eleven months’ 
working to complete the excavation. 
“In its progress, the following strata were cut through in succes- 
sion : — 
gt 
6 feet vegetable mould. 
18 ‘ gray or bluish clay. 
20 “* sand and shingle, enclosing rolled stones of various sizes. 
6 * Jight blue clay. 
3 ‘* rough sand and shingle. 
115 ‘ Old Red Sandstone conglomerate, composed of red clay, quartz, mica 
and rolled stones. 
74 ** alternating strata of compact, fine-grained Red Sandstone, varying in 
thickness from 1 to 7 feet, and clay, varying from 6 inches to 12 feet 
thick. 
8 ‘ Qinches, mica-slate formation, the first two feet of which were chiefly a 
hard, brown quartzose substance, containing iron, manganese, and 
carbonate of lime. 
250 feet, 9 inches. 
‘«‘The temperature of the water at the bottom of the well, when 
completed, was found to be within a fraction of 50° Fahrenheit, and 
the average temperature of the locality, deduced from twenty-three 
years’ observation, by the late George Jnnes, F. R. §., is 47° 1: 
hence, nearly 3 degrees of increase appear as the effects of central 
heat. The supply of water obtained is excellent in quality, and suf- 
