Reports and Proceedings — Geological Society of London. 327 



parts of the world, and at several different geological horizons ; and 

 the relationships of the jaspers and igneous rocks resemble those 

 seen in the radiolarian cherts of Southern Scotland. It is inferred 

 that the jaspers are altered radiolarian cherts. The evidence for the 

 age of the group is incomplete. There is not sufficient evidence to 

 refer it to the Arenig Series, and it is possible that it belongs to an 

 altogether different period. Its relation to the crystalline schists 

 of the region is obscured by conflicting evidence : one chain of 

 reasoning leads to the view that the group is older than the 

 schists, and has been involved in their metamorphism ; while 

 another gives strong reason for supposing that it is of later date. 



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. 



Specimens were collected at intervals, from Budleigh Salterton, 

 in Devon, to Fitzhead near Milverton, in Somerset, and other sands, 

 for comparison, were taken from the red rocks above and below. 

 After treatment with acids, to remove iron-oxides, the sands were 

 separated by heavy liquids into three parts : — 



(«) Heavy residue : specific gravity exceeding 2 -8. 



\b) The biilk of the quartz. 



(c) The lighter part, with most of the alkali-felspar. 



The sands, on the whole, contain a very small percentage of 

 minerals with a specific gravity of more than 2-8 ; while the pro- 

 portion of material over, to that under, 2-58 is about 70 or 80 to 30 

 or 20 per cent. A list and description of twenty minerals found in 

 the sands is given, with, in some instances, the chief characters by 

 which they were identified. The compound grains include felsite, 

 quartzite, chert, shimmer-aggregates, leucoxene, and other decom- 

 position-products. The gradual decrease in the percentage of heavy 

 minerals from Budleigh Salterton to Uffculm indicates the carriage 

 of sediment by a southerly current, and this view is strengthened 

 by the decrease in staurolite and a gradual diminution in the size of 

 the tourmaline-grains. The increase in proportion of heavy grains 

 from Uffculm to Milverton, and the further decline northward, 

 together with the incoming of an assemblage of minerals markedly 

 different from the normal southerly type, indicates an additional 

 source of supply, perhaps a westerly current. The mass of material 

 seems to have been furnished by a highly metamorphosed area, 

 differing widely in its character from any now exposed in the 

 south-west of England. The most probable source of much of 

 the material is the Armorican massif of Triassic times. 



3. " Eevisiou of the Phyllocarida from the Chemung and Waverly 

 Groups of Pennsylvania." By Professor Charles Emerson Beecher, 

 Ph.D., F.C.G.S. 



The specimens described in the paper, as well as those on which 

 the original descriptions were based, were all obtained in the vicinity 

 of Warren, Philadelphia. The chief horizon is in the shale-beds of 

 the Upper Chemung Group, about 50 feet above mean water-level 



