The transformation of sedimentary rocks to a rock of quartz-diorite aspect and mineralogy by a process of granitization, characterized by the introduction of an alkali-felspar magmatic fluid, has recently been described by the writer from the western end of the Criffell-Dalbeattie igneous complex (1937, pp. 471–7).1 In the present paper the geochemistry of this process is considered in the light of supplementary analytical data.

The detailed studies on rocks of the prasinite-green schist facies published during the last decade have thrown a flood of light on the genetic relations of the various members of this facies group. References may be made to the work of Vogt at Sulitelma (l),1 Fischer in the Wippra metamorphic zone (2), Weg's studies in the Saxon Zwischengebirge (3), Turner's contributions on the Otago schists (4), and finally in this country to Wiseman's study of the progressive metamorphism of the Dalradian epidiorites (5).

Recent work on the succession and structure of the Skipton Anticline1 has proved strata about 6,000 feet thick. These beds are of Dinantian age ranging from γ to P2 and are in great contrast to the strata of the Askrigg massif, 8 miles to the north, where the Dinantian is of S1 to P2 age and is only 800 feet thick.

A striking feature of the geology of the Lizard is the occurrence of rocks very rich in, or consisting entirely of epidote; as bands parallel to the foliation of the hornblende-gneiss and the green schists of the Old Lizard Head Series; as lenticles caused by local enlargement of those bands; and sometimes as veins cutting the foliation, for instance on Polurrian Beach. The coast-sections at Mullion do not show great development of these epidotic rocks in the hornblende-gneiss but bands one inch thick occur. At Porthallow and north of Porthoustock there is an even smaller development of these rocks, but along the coast from Pentreath Beach southwards round Lizard Point to Cadgwith epidote bands and lenticles are abundant. Sir John Flett remarks in the 1912 Memoir (p. 50) on the perfection of this banding, “which cannot be paralleled anywhere else in Britain,” but he has told me that in Anglesey epidotic rocks approach them in abundance. These Anglesey rocks were described by Dr. E. Greenly in the Survey Memoir of that area (1919, pp. 108 and 109 inter alia).