78 Geological Society, 



with erratic boulders not less than 80 feet deep, resting on clays — 

 the ' Kolguev Clays.' Mount Bolvana rises as a symmetrical cone 

 above the tundra, detached from the northern plateau, pointing, 

 in the opinion of the author, to the occurrence of marine erosion. 



The southern portion of the island is tundra, a dead flat of grass, 

 bog and peat-levels reaching to the sea; good sections of the 

 Kolguev Clays are exposed in the gullies traversing it near the sea on 

 the western coast. In the vicinity of the Gobista river the Kolguev 

 Beds consist of clays merging here and there into sands. They are 

 charged with boulders often ice-scratched, indicating continuous 

 deposition in a comparatively deep sea. The beds yielded many 

 shells of Arctic mollusca, such as Saxicava arctica, Mya, etc., 

 apparently dispersed from top to bottom. The ice-pack has 

 forced many fragments of semi-fossil wood on to the shore, no 

 doubt worked up from a bed immediately below sea-level. No 

 deposit was met with in Kolguev Island precisely similar to what is 

 called ' Till ' in Scotland, though there are many Boulder Clays in 

 Britain which are in no measure superior in toughness to those of 

 Kolguev, for instance, those of the Yorkshire coast and the Chalky 

 Boulder Clays of Norfolk. 



It is suggestive that all the glacial deposits met with by the 

 author in Arctic and Polar lands (except the terminal moraines 

 now forming above sea-level) should be glacio-marine beds. 



Prof. Bonney in his report describes the rocks brought home by 

 the author. They include granite-gneiss (very like Archaean rocks), 

 grit, chert, limestone with Favo'sites (Silurian or Devonian), lime- 

 stone with Amphijpora ramosa (Devonian), limestone with Litho- 

 strotion irregulare (Carboniferous), and a fragment of a Jurassic 

 belemnite. The fossils have been examined by Mr. E. T. Newton, 

 F.R.S. 



IX. Intelligence and Miscellaneous Articles. 



ON UNDERGROUND TEMPERATURES AT GREAT DEPTHS. 

 BY ALEXANDER AGASSIZ. 



T^OR several years past I have, with the assistance of our 

 -*- engineer, Mr. Preston 0. I\ West, been making rock-tempe- 

 rature observations as we increased the depth at which the mining 

 operations of the Calumet and Hecla Mining Co. were carried on. 

 We have now attained at our deepest point a vertical depth of 

 4712 feet, and have taken temperatures of the rock at 105 feet, at 

 the depth of the level of Lake Superior, 655 feet, at that of the 

 level of the sea, 1257 feet, at that of the deepest part of Lake 

 Superior, 1663 feet, and at four additional stations, each respec- 

 tively 550, 550, 561, and 1256 feet below the preceding one, the 

 deepest point at which temperatures have been taken being 4580 

 feet. We propose, when we have reached our final depth, 4900 



