

AUGITE-FELSPAR ROCKS OF SCOTLAND. 309 



are intruded into the carboniferous limestone, but are probably of 

 carboniferous age. 



Volcanoes of Fife. The volcanic rocks of Fife are separated by 

 the Dysart and Leven Coalfields. In West Fife one group of old 

 volcanic vents was situate in the district now occupied by the Saline 

 and Cleish Hills, and is represented by some cones of fine green tuff. 

 Another group lies six or eight miles to the east, near Burntislam 

 The tuffs and lavas occupy nearly the whole interval between 

 the Burdie House limestone, and the base of the carboniferous 

 limestone. The interstratification of the rocks is well seen on the 

 coast between Burntisland and Kinghorn, especially between Petty- 

 cur and Seafield Tower. These volcanic outbursts are contemporary 

 with those of West Lothian, and the basalts reach a thickness of 

 upwards of 1500 feet. 



The East Fife district contains an extraordinary number of 

 volcanic vents, several of which are well seen on the coast They 

 extend in a band six miles wide from Leven to St. Andrews, where 

 about fifty volcanic vents are now filled with tuff and agglomerate or 

 masses of basalt ; but these rocks are almost unconnected with inter- 

 bedded volcanic rocks. The outbursts probably belong to the close 

 of the Carboniferous period. 



Professor Geikie remarks that the Campsie Fells and Kilpatrick 

 Hills are only the north-eastern extremity of the great volcanic 

 plateau of Dumbartonshire, Renfrewshire, and Ayrshire, and that the 

 Garlton Hills of Haddington are to be connected with the outbursts 

 along the southern flank of the Silurian uplands from Duns in 

 Berwickshire ; by Kelso, Ruberslaw, Langholm, Birinswark, and the 

 Annan, to the mouth of the Nith at the foot of Criffel. 



The Clyde Basin. In the Clyde Basin Coalfield interbedded dole- 

 rite and ash form the hills of Kilsyth, Campsie, and Kilpatrick on 

 the north, and the Renfrewshire hills on the south, where they occur 

 at the base of the carboniferous limestone. The intrusive sheet of the 

 Necropolis Hill, Glasgow, is a micaceous dolerite, sometimes dark 

 grey, sometimes reddish brown. 1 



Varieties of Doleritic Rocks in Scotland. Dr. Archibald Geikie 

 describes the augite-felspar rocks in three varieties, which he terms 

 diabase, dolerite, and basalt. The diabase is more coarsely crystalline, 

 varies in colour with the tint of the felspar and with the development 

 of decomposition, so that although some are pink, most are green. 

 They are never amygdaloidaL Orthoclase usually occurs to the 

 almost total exclusion of plagioclase, and when plagioclase does occur 

 it is probably never labradorite. Augite is the most conspicuous 

 mineral under the microscope, and is but little altered. The other 

 minerals are titaniferous iron and apatite. No olivine crystals are 

 seen, though serpentine occurs as a decomposition product. Quartz 

 is occasionally present, but usually as a product of decomposition. 

 Brown biotite and small prisms of hornblende are found when the 

 rock is greatly altered. 



1 Allport : " Carbon Dolerites," Q. J. G. S., vol. xxx. 



