BRITISH ASSOCIATION. 



251 



4. Inclined strata. This structure Dr. Stark endeavoured 

 to explain as one superinduced after the accidental destruc- 

 tion of the lines of stratification which formerly existed. In 

 conclusion, Dr. Stark observed, that all the above forms of 

 stratification might be expected to occur in the extent of a 

 single glacier. 



Dr. Richardson observed, that snow constantly disappeared in 

 great quantities without melting; in dry frosty air, with a temperature 

 below zero, it would disappear rapidly by insensible evaporation. The 

 prismatic form of ice, which occurs on lakes where it has attained a 

 thickness of 6 or 8 feet, takes place only in the spring when it begins to 

 melt ; the particles were considered to undergo a new arrangement when 

 the temperature of the mass was elevated to the melting point. 



Col. Sabine had seen the ribboned structure of glacial ice men- 

 tioned by Prof. Forbes, but doubted whether it had ever been seen 

 in polar ice ; he had never met with it, and did not think it would have 

 escaped his observation. 



On the Western States of North America, by Dr. Dale 



Owen, 



The Memoir was illustrated by Maps, Sections, and 

 Diagrams of Fossils. 



The grand feature of the country is the Illinois Coalfield, 

 equal in extent to all England, separated from another 

 coalfield, that of the Ohio, by an axis of much older rocks ; 

 the object of the memoir was to identify tliose lower rocks 

 with the systems which supported our own carboniferous 

 series. But we need not give an abstract of this paper at 

 present, as it will be read at the next meeting of the Geo- 

 logical Society. 



Mr. Phillips compared the extreme simplicity in the 

 succession of strata and distribution of organic remains 

 observable in these districts of N. America under considera- 



