A Remarkable pegmatite occurring on Bittleford Down (Wind Tor), near Widecombe, is described in the Survey Memoir as a veinrock containing (a) abundant hornblende, a mineral not previously found in any of the post-Carboniferous granites of the west of England, (b) much sphene, (c) porphyritic crystals of oligoclase, and (d) quartz crowded with fluid inclusions.

This rock is of peculiar interest in other respects. Its complete freedom from biotite and its high content of felspar (oligoclase dominant over orthoclase) imply considerable deviation in bulk composition from the normal Dartmoor granite. Moreover, its accessory minerals include both gold and silver.

Considered broadly as a coarse-grained felsic type, its position in the list of variants from the normal granite is shared by a still more felsic rock with which it is closely associated in the field.

In September 1923 a visit to the lead-mining district of Holywell, Flintshire, so closely associated with the name of Thomas Pennant, was organized by Mr. Campbell Smith in order to examine the abandoned workings with a view to collecting specimens. The occurrence of the ores has been described in detail by Sir Aubrey Strahan and Mr. Bernard Smith, and reference to many mineral localities, mentioned by Pennant, is made by Mr. Campbell Smith (loc. cit.).

The commoner specimens collected consist of ruby-blende (Talargoch mine), botryoidal and pseudomorphous calamine ZnCO3 (Milwr mine), orange and reddish-mauve fluor with bitumen and blende (Bryn-gwiog mine).

Calcite also occurs abundantly in veins and cavities throughout the limestone, the crystals usually consisting of large modified obtuse rhombohedra.

At the November (1923) meeting of the Society I gave an account of a new find of euclase of peculiar habit and of native platinum from the gold and diamond washings in British Guiana. The occurrence of platinum being a new record for that country, the announcement was naturally received there with some interest—but also with some scepticism. Mr. J. C. Menzies, by whom the platinum was found, has been accused of ‘salting’ the locality, or, alternatively, doubt has been cast on the correctness of my determination. The euclase aggregates, thought by Mr. Menzies to be fossils, could certainly not have been used by him for ‘salting’; and as the platinum (together with some small, silvery scales of mica) came with these, I have no reason to doubt his bona tides. I am also quite satisfied with the correctness of my determination of the material as platinum, as set out in detail on p. 191 of this volume.