378 Reports and Proceedings — Geological Society of London. 



of Colorado, though not so definitely crystalline, also contains tabular 

 crystals which are orthorhombic in symmetry, and probably identical 

 in mineral characters with those of South Australia. From the 

 general characters of these crystals, it appears that carnotite is a mineral 

 belonging to the Uranite group, and that it may be regarded as the 

 vanadium analogue of autunite. The black lodestuff in which the 

 Radium Hill carnotite occurs is heterogeneous in constitution. It 

 consists essentially of ilmenite, which is impregnated with magnetite, 

 rutile, carnotite, and a mineral which is possibly tscheffkinite. The 

 evidence provided by a study of the complex does not necessitate the 

 view that new minerals are present, such as that to which the name 

 ' davidite ' has been given. — On the species Pilolite, and the analysis 

 of a specimen from China; by Mr. G. S. Whitby. The specimen 

 examined is from a new source, and possesses the formula Alg O3 . 2 Si Og, 

 2 (Mg . 2 Si Oo), 7II3 ; a formula which is simpler than those given 

 by Heddle and by Friedel to the pilolites which they investigated. 

 The author considered that for the present the term pilolite should 

 be applied to those varieties of mountain leather and mountain cork 

 which (1) cannot be referred to asbestos on account of theii' large 

 water-content, (2) cannot be identified with serpentinous asbestos on 

 account of the relatively small amount of magnesia which they contain, 

 and (3) hold their water in such a way that when it has been expelled 

 by heating it is gradually re-absorbed to its original amount from the 

 atmosphere. — Phenakite from Brazil ; by Dr. G. F. Herbert Smith. 

 Crystals of phenakite recently discovered at the gold-mine, San Miguel 

 de Piracicaba, Brazil, all display the new form {2352} noted by other 

 observers, and another {4596} lying near it. The tetrahedral character 

 of the symmetry is clearly marked. — Preliminary note on the occurrence 

 of Gyrolite in Ireland; by Mr. F. !N. A. Fleischmann. The mineral 

 gyrolite, though well known as occurring in the basalts of the Western 

 Islands of Scotland, has not hitherto been recorded from Ireland. 

 Specimens have now been found in the basalts and dolerites in the 

 neighbourhood of Belfast. The mineral occurs in small spherical 

 aggregates, forming a crust on f aroelite ; it is associated with apophyllite 

 and occasionally with chabazite. The chemical composition and the 

 optical characters of the mineral agree with those of gyrolite. The 

 mineral is found only in the harder and denser la)'ers of the basalt, and 

 never in the soft highly amygdaloidal layers. 



II. — Geological Society of London. 



June 16, 1909.— Professor W. J. Sollas, LL.D., Sc.D., F.R.S., 



President, in the Chair. 



The following communications were read : — 



1. "The Carboniferous Limestone of County Clare." By James 

 Archibald Douglas, M.A., B.Sc, F.G.S. 



The district with which this paper deals forms the westernmost 

 limit of the great central Carboniferous Limestone plain of Ireland. 



The limestone floors nearly the whole of Eastern Clare, from the 

 southern shore of Galway Bay to the banks of the Shannon. This 

 area, for the purposes of description, is divided into two main districts. 



