TRANSACTIONS OF SECTION C. 665 



8. On Manganese lilimng in MerioneihsMre. 

 By C. Le Neye Foster, B.Sc. 



Manganese ore is now being ■worked in tlie Cambrian rocks at several places 

 near Barmouth and Harlech. It occurs in the form of a bed varying from a few 

 inches to 4 feet in thickness ; the average thickness is 18 inches to 2 feet. The 

 undecomposed ore contains the manganese in the form of carbonate, with a small 

 proportion of silicate ; but at the outcrop it is changed into a hydrated black oxide. 

 Some of the outcrops of the manganese bed are erroneously marked on the geological 

 survey maps as mineral veins, though Sir Andrew Ramsay was of opinion that 

 the deposits were not true lodes. Recent workings show plainly that the deposits 

 are truly stratified beds, or possibly various outcrops of one and the same bed, 

 extending over a considerable area. 



The ore contains from 20 to 35 per cent, of metallic manganese, and is de- 

 spatched to Flintshire and Lancashire for the manufacture of ferro-manganese. 

 The new Merionethshire mines are the first instance of workings for carbonate of 

 manganese in the British Isles. 



9. On the Exploration of Ray gill Fissure, in Lothersdale, Yorlcsliire. 

 By Jajies W. Davis, F.G.S.— See Reports, p. 4G9. 



WEDXESDAY, SEPTEMBER 8. 

 The following Papers and Reports were read : — 



1. On tlie Basalt of Rowley Regis. By C. Beale. 



The basalt of Rowley Regis appears at the surface as an irregular, roughly trian- 

 gular mass, having the base (rather more than one mUe and a half wide) towards 

 the north, and with a length of about two miles and a quarter. Its thickness varies 

 much ; in quarries the exposed face of rock amounts to 150 feet; at Rowley HiU 

 Colliery it was about 300 feet thick. The rock also varies much in structure ; it is 

 divided by layers of ' rotch,' or decomposed basalt ; the lower beds of the solid rock 

 are fine-grained, those above are often more coarsely crystalline. 



2. On the Mineral District of Western Shropshire. 

 By C. J. Woodward, B.Sc. 



The minerals of Western Shropshire occur in the Llandeilo Flags, which, as 

 will be seen by reference to the ordnance map, occupy a patch of country, of a 

 somewhat pear-shaped section, the base of which is to the south-west, and the 

 narrow portion to the north-east. In the flags occur patches of the so-called green- 

 stone of the survey, and there are numerous bands of felspathic ash, the outcrop 

 of which has a general direction of north-east and south-west. The mineral lodes 

 run generally east and west, in many cases crossing the felspathic bands. 



Many mines have been opened in the district, but at the present time only three 

 are worked, viz.. Roman Gravels, Snailbeach, and Wotherton ; the last named is a 

 barytes mine, and the two former are lead mines. Some years ago, in one of the 

 levels of Snailbeach mine, were found extremely fine rhombs of violet and pink calcite, 

 with brilliant crystals of quartz, blende, galena, and pyrites. These fine showy crys- 

 tals are now scarce, but some examples are preserved in the office of the mine. The 

 galena commonly shows faces of the octahedron and cube, and occurs, or did occur, in 

 masses of some hundredweights. The Roman Gravels mine yields galena and 

 blende, but principally in the massive form. At some of the disused mines are to 

 be found fine crystals of blende, not only of the usual dark colour, but also in 



