286 KEPORTS ON THE STATE OF SCIENCE. 



No. 422a. Diorlte. 

 Any. 7 S. W. Sodneithior, E. side house. 



I. II. 



SiO., 45-21 45-13 



Diorite from Bodneithior, Llandyfrydog. It is a less basic portion of 

 one of the Post-Ordovician intrusions, the more basic (and larger) portion 

 of -which is the famous hornblende-picrite. For an analysis of that rock 

 see Teall, ' Brit. Petrography,' p. 103. 



No. 514a.. Bulerite. 

 Any. 8 S. W. Small dyke iV. of IHnas, Traeth Bychan. 



I. II. 



SiO„ 47-35 47-29 



A small basic dyke traversing the Carboniferous limestone on the 

 east coast near Moelfre. The only one known in that district. 



Besides these rocks, a suite of six silica percentages have been 

 estimated, each in duplicate, of the very curious altered rocks of Pai-ys 

 Mountain, -which have lately been shown to be of Silurian age, and in 

 which the once famous copper mines (still worked by a solution process) 

 are situated. The filtrates are reserved for treatment later on. 



On some of the methods Mr. Hughes remarks : — 



' The methods employed in the above analyses were described in 

 the report of last year, and no modifications of these, or new methods 

 have been introduced. 



' A large number of determinations of alkalies made by the Lawrence 

 Smith method proves that the method, besides being a convenient one, 

 is also very accurate, and great reliance can be placed upon it. 



' The steel crusher bought last year continues to give satisfaction, 

 and by its use considerable saving of time is effected in the preliminary 

 process of reducing the rock to powder. This, as well as all other 

 steel apparatus — hammer, mortars, tfec. — are kept in a galvanised iron 

 tank, with a tightly fitting cover, containing lime ; in this way rusting 

 is entirely prevented.' 



There is still a small balance left, about equal to the amount expended 

 in the course of the past year. The Committee ask to be reappointed, 

 and to retain this balance for use in the coming twelvemonth. 



Investigation of the iwe-Devonian Boclcs of the Mendips and the Bristol 

 Area. — Beport of the Committee, consisting of Mr. H. B. Wood- 

 ward {Ghairman), Professor S. H. Reynolds {Secretarij), Dr. 

 C. Lloyd Morgan, and Rev. H. H. Winwood. {Brawn iijp hy 

 the Secretary.) 



The pre-Devonian Rocks of the Bristol district include the two inliers of 

 the Eastern Mendips and of Tortworth. 



The Eastern Mendip Inlier. 



The grant from the British Association, the object of which was to 

 assist the Secretary in studying the Silurian rocks of the Bristol district, 



