Notices of Memoirs — The British Association. 565 



on each side. These zones or " pay streaks " do not appear to be the 

 effect of any law that has yet been applied to our mines. 



Judging from the available fossil evidence, which however is 

 small, the gold-bearing beds appear to be of Cambrian age. 



The quartz mills of Nova Scotia are similar to those in general 

 use in Australia and California. The cost of mining varies from 

 eighty cents in the open cast slate belts, carrying auriferous quartz, 

 up to fifteen dollars a ton in small veins, three or four inches wide 

 in very hard. rock. The cost per ton of crushing with water power 

 varies from sixty cents to one dollar, with steam power the cost is 

 somewhat higher. 



Attention is now being turned to low grade ores, that is to say, 

 beds of auriferous slate with veins of quartz, yielding averages of 

 four to eight pennyweights of gold to the ton. 



During the year 1883 the miners averaged two dollars eighty-four 

 cents a day from 25,954 tons of quartz, yielding ten pennyweights 

 and twenty-one grains of gold per ton, and looking at the lai'ge 

 extent of country containing proved auriferous strata, the author 

 anticipates a permanent and profitable future for the gold mines of 

 Nova Scotia. 



8. — Marginal Kames. 

 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 hacTcward drainage of the melting edge of the glacier, 

 and for which he proposed the name marginal hames. 



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. Ho 

 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 witliout, that they 

 have a rude anticlinal structure, that boulders and till often lie on 

 the 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 back- 

 ward or into the ice. A study of 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 Green- 



