282 Reports and Proceedings — 



in question ; but the latter was not based on any fresh facts or 

 observations. 



The author's own observations on the subject, carried on during 

 many years, were detailed and illustrated by a map of the whole of 

 the Taconic range. In conclusion, he pointed out that, even if Dr. 

 Sterry Hunt's general principle were conceded, and he was not by 

 any means himself prepared to make such a concession, it would 

 have no bearing on the point at issue ; for the supposed younger 

 strata do not dip against the Taconic schists. In opposition to the 

 view that the geological age of strata can be inferred from their 

 mineral characters, he pointed out what remarkably different rocks 

 have been produced by the metamorphism, in different degrees, of 

 the strata of the Taconic range. 



2. " On some Nodular Felsites in the Bala Group of North 

 Wales." By Prof T. G. Bonney, M.A., F.R.S., Sec. G.S. 



These peculiar felsites are chiefly found in one or two localities 

 in the neighbourhood of Bettws-y-Coed and of Conway. In the 

 former case, in the same mass, are found ordinary compact felsite, 

 exhibiting under the micvoscoiDe fluidal structure, a peculiar rock, 

 resembling a greenish schist, and vai'ious nodular felsites (witli 

 cleavage) showing nodules sometimes 3 or 4 inches in diameter, 

 some being solid, others hollow, or more or less filled with chalcedony, 

 chlorite, chalybite, etc. The nodules never exhibit a radial struc- 

 ture, and there is no difference of importance between their struc- 

 ture and that of the ordinary rock. The author showed that the 

 schisty rock is only an amygdaloidal felsite, in which, after cleavage, 

 a secondary (micaceous ?) mineral has been deposited along the 

 cleavage-planes. As regards the nodular structure, he showed that 

 it is analogous to the spheroidal structure seen on a large scale in 

 many igneous rocks, and on a smaller scale in perlite, and gave 

 reasons for its being frequently associated with vesicular cavities. 

 The infiltration of these cavities and consequent solidification was 

 almost certainly prior to the production of the cleavage-surfaces, 

 which are distorted by them. The Conway felsites exhibit similar 

 phenomena, except that they are practically uncleaved. 



3. " On the Cambrian (Sedgw.) and Silurian Eocks of Scandi- 

 navia." By J. E. Marr, Esq., B.A., E.G.S. 



The author has examined the following areas of Cambrian and 

 Silurian rocks in Scandinavia: — (1) Dalecarlia, (2) Ostrogothia and 

 Westrogothia, (3) Christiania, (4) Scania, (5) Baltic Isles. A sketch 

 of the stratigraphy of each of these regions was given, and the author 

 gave the following conclusions : — 



/ Mudstones of Ramsasa and Bjersjolagard = Ludlow. 



Silurian. < Cardiola beds: Cyrlograptiis and Betiolites Shales = Wenlock. 

 \ Lobiferus Shales: Upper part of Brachiopod beds = May Hill. 



/ Lower part of Brachiopod beds = Upper Bala. 



Cambrian ) ^''^'^«<^^*"* Shales : Beyrichii Limestone = Middle Bala. 



■ J Kargarde Shales : Cystidean Limestone = Lower Bala. 



\ etc. = etc. 



A correlation with the beds of Bohemia was also given. The 



