lxxxil PROCEEDINGS OF THE GEOLOGICAL socinty. [May 1902. 
The specimens are of interest as showing :— 
(i) The existence of metalliferous veins in Ordovician rocks which have been 
formed in pre-Carboniferous times; for the Shap Granite which has produced 
the alteration is itself pre-Carboniferous. 
(ii) The alteration of a metalliferous vein of complex ccmposition by pyro- 
metamorphism,—an occurrence which the exhibitor believed had not previously 
been recorded. 
Giii) The possibility that some of the highly crystalline rocks of a complex 
of regionally metamorphosed rocks may owe their characters to hydrothermal 
action having formed veins along the parallel divisional planes of pre-existing 
rocks, these veins having been subsequently altered by pyrometamorphism. 
Mr. H. W. Moncxton exhibited a Flint-Implement which he had 
himself found on a heap of gravel, in a pit 278 feet above Ordnance- 
datum, at Englefield (Berkshire). The gravel is part of an elongated 
patch mapped ‘ Plateau-Gravel.’ He had great pleasure in handing 
over the implement to Mr. O. A. Shrubsole, F.G.S., to be placed in 
the Reading Museum. 
Mr. O. A. SurvssoLe remarked that the implement was of paleo- 
lithic type, and of an advanced form of that type, as it had a cutting- 
edge all round. It had not been greatly rolled, and was probably 
made not far from the spot where it was found. Its patination 
showed that it belonged to the gravel in which it was found. 
The following communications were read ;— 
1. ‘ The Origin and Associations of the Jaspers of South-eastern 
Anglesey.’ By Edward Greenly, Esy., F.G.S. 
2. ‘The Mineralogical Constitution of the Finer Material of the 
Bunter Pebble-Bed in the West of England.’ By Herbert Henry 
Thomas, Esq., B.A., F.G.S. 
3. ‘ Revision of the Phyllocarida from the Chemung and Waverly 
Groups of Pennsylvania.’ By Prof. Charles Emerson Beecher, 
PhD ECGS. 
In addition to those mentioned above, the following specimens, etc. 
were exhibited :— 
Rock-Sections, Lantern-Slides, Photographs, and Maps, exhibited 
by E. Greenly, Esq., F.G.8., in illustration of his paper: including 
Playertype Photographs of 6-inch Field-Maps of the Pentraeth and — 
Newborough districts, and original 25-inch Maps of part of the 
latter district. 
Rock-Sections and Lantern-Slides, exhibited by H. H. Thomas, 
Esq., B.A., F.G.S., in illustration of his paper. 
Teeth of Lamna, from near the base of the Thanet Sands, Erith 
(Kent), exhibited by Prof. H. G. Seeley, F.R.S., V.P.G.S8. 
Paleolith from Welwyn (Hertfordshire), exhibited by A. E. 
Salter, Esq., B.Sc., F.G.S. 
