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of felspatliic greenstone, the outpouring of which and forma- 
tion of beds must have been contemporaneous with the 
deposit of the mud of which the clay schists are made up. 
These phenomena are nowhere better developed than on the 
peninsula of Langness and all along the eastern coast from 
Cass-na-awin (at the mouth of the Santon burn) to Maug- 
hold Head. 
“These schists have been highly contorted by the subse- 
quent intrusion of granites and porphyries, but their general 
dip is to the N.W. and S.E. of the range of mountains run- 
ning from the Calf of Man to North Barrule, which has a 
general direction from S.W. to N.E. corresponding with the 
strike of the schists. 
“ The granite has protruded at Foxdale, on the eastern side 
of South Barrule, and at the Dhoon, north of Laxey, greatly 
altering the schists where in contact with them. The age 
of these granite bosses is uncertain. 
“In the neighbourhood of the granites the most productive 
mineral veins have been discovered. Large masses of white 
quartz lie along the strike of the schists, and a vein of it 
cutting through the eastern side of the granite of Foxdale 
is at least 30 feet thick. The thickness of these old schists 
is enormous, and must be calculated at many thousands of 
feet, making every allowance for the existence of faults, for 
we may walk across the upturned edges, and trace them 
layer imposed upon layer through great distances. We 
have one small portion of them in the form of a blue fibrous 
and elastic flagstone at Spanish Head and the Chasms lying 
almost horizontal, and having a vertical thickness of more 
than 300 feet. 
“ There are no distinct evidences of true slaty cleavage in 
these schists; the partings in the so-called slates of South 
Barrule being in the direction of the bedding. An imperfect 
