The Quarterly journal of the Geological Society of London . f the Camp, there remains much groundwhich the present paper leaves untouched. The points from which the different specimens were derived aremarked with some approximation to truth on the accompanyingoutline map, on which the geological boundaries laid down on thepublished Survey map are indicated. The Arabic numerals refer tothe numbers with which the specimens of felsite, derived fromthose spots, were ticketed, while the Roman numerals denote basiceruptive rocks. The numbering of the specimens and sectionsbears no relation to any se
The Quarterly journal of the Geological Society of London . f the Camp, there remains much groundwhich the present paper leaves untouched. The points from which the different specimens were derived aremarked with some approximation to truth on the accompanyingoutline map, on which the geological boundaries laid down on thepublished Survey map are indicated. The Arabic numerals refer tothe numbers with which the specimens of felsite, derived fromthose spots, were ticketed, while the Roman numerals denote basiceruptive rocks. The numbering of the specimens and sectionsbears no relation to any sequence in the field or relation of therocks to one another, and has merely been retained to avoid anypossible source of error from re-labelling. II. The Melaphyre Series. The following are descriptions of certain selected types of theMelaphyre Series. No. XII. side of Caer Caradoc, near the top of the vesicular basalt-glass. (Melaphyre.) CARADOC AND ADJACENT HILLS TO THE SOUTH. J\f(ilapJiyros in, J?oni(f/h - Melaphyre, =3 I MILE Felsites (Khyolites) 1, 5, 6, and 9:—more or less splierulitic and vesicular.„ ,, 2, 3:—vesicular, with elongation of vesicles. „ 4, 11, 13, 10, 17 :—perlitic.„ 18:—Ehyolite tuff. 536 MR. F. RUTLEY ON SOME OF THE A dark bluish-grey, vesicular rock, the vesicles being mostly filledwith pale greyish-white or dark green substances. The weatheredsurfaces are rusty-brown and the amygdules at the surface haveusually decomposed, leaving empty pores which impart a somewhatBcoriaceous aspect to the rock. Under the microscope, in thin section,it is seen to consist of once glassy matter, now more or less devitrifiedby the development of microliths and globulites, and crowded withsmall granules and crystals of magnetite, together with little needlesand skeleton crystals, often twinned, and these from their extinction-angles appear in many instances to be labradorite. There are alsomany small lath-shaped crystals o
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