574 Miscellaneous. 



giving some account of the excursions made during the year. 

 Dr. Callaway contributes a short essay on Pre-Cambrian Volcanoes^ 

 as evidenced by the Uriconian rocks of Malvern and elsewhei'e. 

 The ' Charnian ' rocks of Charnvvood Forest are regarded as the 

 equivalent, at least partially, of the Uriconian. in tlie sam& 

 Journal Mr. L. Richardson gives an interesting account of the 

 Ehsetic beds of Worcestershire; and Messrs. J. W. Gray and 

 G. W. S. Brewer contribute an article on evidences of ancient 

 occupation on Cleeve Hill, with an appendix on the vertebrate and 

 molluscan remains by Messi's. M. A. C. Hinton and A. S. Kennard. 

 The human settlement appears to have belonged to the Iron age, 

 and the domesticated animals included the horse, ox, sheep, pig, 

 and fowl. The Cotteswold Club has also issued (as a Supplement 

 to vol. xiv) a useful Table of the Contents of the Proceedings, 

 vols, i to xiv, 1847-1903. In this the title of the first printed paper 

 should have been given — it is " On the Geology of the district 

 explored by the Cotteswolds Club, and more particularly of the 

 Clay subsoil of the [Royal Agricultural] College Farm," by S. P. 

 Woodward, pp. 2-8. 



Tertiary Plutonic Rouks from the Isle of Rum.' — Mr. Alfred 

 Harker, M.A., F.R.S., writing on the Plutonic rocks of Tertiary age, 

 which make up about one-half of Rum, states that the ultrabasic 

 group is the most important. It includes various peridotites, some 

 essentially of olivine, but others containing pyroxenes, and especially 

 anorthite. A noteworthy amount of lime and alumina, giving rise 

 to anorthite, is indeed a special characteristic of the group. Equally 

 striking is a tendency to separation of the more peridotic and the 

 more felspathic portions of the magma, usually with a stratiform 

 disposition. With bands of true peridotite alternate others of alli- 

 valite, a rock consisting of anorthite (predominant) and olivine, and 

 even containing seams of pure anorthite rock. Another peculiar type, 

 styled harrisite, is composed essentially of olivine (predominant) and 

 anorthite, the olivine occurring here as large lustrous black crystals, 

 with good cleavage. 



Later than all these rocks, and intruded beneath them, comes the 

 eucrite group, which shows less variety. The rocks are usually 

 somewhat rich in olivine ; much of the pyroxene is hypersthene, and 

 the felspar is near anorthite. Still later comes the granite group, 

 mostly hornblendic and often with granophyric structures. Th© 

 acid magma has entered into peculiarly intimate relations with the 

 eucrite, not only metamorphosing and impregnating that rock, but 

 enclosing and partially incorporating portions of it, large and small. 

 The enclosed portions, in a half-digested state, have been streaked 

 out by movement, and there has arisen a group of well-banded 

 gneisses, closely resembling the Lewisian of the north-western 

 highlands. These Tertiary gneisses are all of the nature of hybrid 

 and composite rocks, of which the contributing elements are the 

 eucrite and the granite, and their genesis can be ti'aced step by step 

 in the field. r 



1 Eead before the British Association, Cambridge, Section C (Geology), Aug., 1904. 



