282 Correspondence — Mr. W. T. Aveling. 



Prof. A. E. Nordenskiold next described some new discoveries of 

 minerals at Nordmarken and Langban in the Province Wermland. 

 Magnificent crystals of zinkblende, in tetrahedrons with one-inch 

 edges, of magnetic iron-pyrites, etc., had been found. The Pro- 

 fessor then made some remarks in connexion with a paper : " Om 

 de Nordenskioldske joernmasser" (On the Nordenskioldian Iron- 

 masses) by Kand. K. A. Y. Steenstrup. 



Geologiska Foreningens I Stockholm Forhandlingen. 

 (Proceedings of the Geological Society of Stockholm.) 



Vol. III. No. 1. (Contents). — Nordenstrom, G. Further Account of the Solstad 

 Copper-mine in Sweden. — Gumselius, 0. Some Observations on the Glacial Deposits 

 of Sweden. — Thorold, A, F. Is the Length of Time wanted for the Eeproduction of 

 Lake- and Bog-ores known ? and if so, how large is that Time ? — List of Members of 

 the Geol. Soc. of Stockholm at the beginning of the year 1876. 



Yol. III. No. 2. — Sjogren, A. On the Mode of Occurrence of the Taberg Iron- 

 ore in the Province Smaland, Sweden. — Pettersen, K. On Serpentine- and Olivine- 

 rocks in Northern Norway. — Linnarsson, G. Geological Observations during a 

 journey on Oland. 



Vol. III. No. 3. — Lundgren, B. On the Species of Inoceramus in the Cretaceous 

 Beds of Sweden. — Hoist, N. 0. On the Glacial Gravel-ridges (Asar).— Widman, 0. 

 Contribution to the Knowledge of the Composition of Condrodite. — Engstrom, N. 

 Analysis of so-called pale Knebelit from Dannemora. (The mineral is, according to 

 Prof. Nordenskiold, Pyrosmalite). — Nordenskiold, A. E. Kupfferpecherz from Ural. 



c OI^:E^:E s IPO isrxD JE isrc DE . 



ABSENCE OF THE LLANDOVERY ROCKS IN THE LAKE DISTRICT. 



Sir, — I see in his Table of Silurian Strata,^ Mr. Hicks assumes that 

 both the Upper and Lower Llandovery beds are represented in the 

 Lake District. This is not the case, both the Upper and Lower 

 Llandovery are absent in the Lake District. The lowest beds of the 

 Upper Silurian in the Lake District are the equivalents of the Tarannon 

 Shales (locally called Stockdale Shales), lying at the base of the 

 Coniston Grits and Flags, which are equivalent to the Denbighshire 

 Grits and Flags. 



The Tarannon or Stockdale Shales, with which are associated the 

 black Graptolitic mudstones, rest, with a very slight unconformity, 

 on the Coniston Limestone series, which is not the representative of 

 the Hirnant Limestone only (a small calcareous band near the top 

 of the Bala Beds in North Wales), but of a much greater thickness 

 of the Bala series. The Coniston Limestone series consists of various 

 thicknesses of shale, limestone, and ashy sandstone. Between this 

 series and the great subaerial volcanic series of the Lake District 

 there is, as I have before shown,'^ a considerable break. 



Kendal, 1th April, 1876, W. Talbot Aveline. 



WASTE OF INSULAR LAND BY THE SEA. 



Sir, — Some time ago I came across an ancient map showing, at 

 three different periods, the size and form of the Island Helgelandt 

 (Helgoland). Even if the map is not strictly accurate, it may, I 

 think, be considered approximately so, and worthy of being repro- 



1 Geol. Mag. April, 1876. 2 q^ol. Mag. Vol. IX. p. 441. . 



