720 REPORT — 1884. 



Hudson they rise to 1,000 feet, at Albany 200, in the Champlain Valley, 350, at 

 Montreal 500, in Labrador 800, at Davis Strait 1 ,000, and at Polaris Bay, as re- 

 ported by Dr. Bissell, 1,600 feet above the ocean level. These clays contain Arctic 

 shells from New York to Greenland, and hence are shown to have been deposited 

 during the ice period. 



The elevation of the northern position of the continent during the Tertiary — 

 when land connection existed between America and Asia and between America and 

 Europe, while a mild climate prevailed at the north — and the depression of the 

 northern half of the Continent during the ice period make it impossible to accept 

 the Lyellian hypothesis of topographical changes as causes of these differences of 

 climate, and compel us to look to some extraneous influence for the cause of the cold 

 of the ice period. 



2. Marginal Karnes. By Professor H. Carvill Lewis, M.A. 



During his exploration of the extreme southern edge of the ice-sheet in 

 Pennsylvania the author had an opportunity of studying certain short ridges of 

 stratified drift which appeared to represent in many cases a backicard drainage of 

 the melting edge of the glacier, and for which he proposed the name marginal 

 kames. 



After describing the general characters of kames, eskers, and osars, as studied 

 in different parts of the world, the author reviewed the researches of American 

 geologists upon this subject, and discussed the various theories as to the origin of 

 these curious deposits. He then described in detail a number of marginal kames 

 in Pennsylvania, indicating their relationship to the great terminal moraine (from 

 which they are clearly to be distinguished), and to the lines of the present drainage. 

 He showed that these kames are made of stratified sand and gravel, finest within 

 and often coarse without, that they have a rude anticlinal structure, that 

 boulders and till often lie on top of them, that they contain no shells or other 

 indications of having been 'shore-lines of any kind, and that while bearing no 

 relation to the movement of the glacier, their courses coincide with the general 

 drainage of the region in which they lie. 



It was argued that marginal kames are due to sub-glacial streams draining the 

 edge of the ice-sheet. When the terminal moraine rested against an upward 

 slope this sub-glacial drainage was backward or into the ice. A study ef the 

 terminal moraine had led the author to the same conclusion, and a number of 

 examples were given to show in certain places the absence of any drainage 

 outwards from the glacier. 



Finally, the sub-glacial drainage of the modern glaciers of Greenland and 

 of Alaska was alluded to, as also the aqueous nature of much of the till in the 

 lowlands, all of which strengthened the conclusion arrived at concerning marginal 

 kames, and concerning an extended sub-glacial drainage of the American ice- 

 sheet. 



(The paper was illustrated by a number of lantern views of kames and 

 moraines, most of them from photographs taken in the field.) 



3. Twelfth Report on the Erratic Blocks of England, Wales, and Ireland. 



See Reports, p. 219. 



4. On Fluxion- Structure in Till. 1 By Hugh Miller, A.B.S.M., F.G.S. 



It has long been recognised as one of the characteristics of the till that its 

 long-shaped boulders are striated lengthwise. They have, as it has been concisely 

 expressed, been 'launched forward end-on.' From the minute and magnifiable 

 striae upon the smaller (e.g. almond-sized) boulders it also appears that these at 



1 Published as part ii. of a Paper ' On Boulder Glacia'ion,' Royal Physical Society 

 of Edinburgh, 1881. 



