REVIEWS. 741 



tainly they are not unaltered glacial deposits ; and to assume that they 

 are derived from such is to imply that no agency but glaciers is com- 

 petent to move boulders of several feet in diameter. Russell refers to 

 the occurrence of large angular rock masses on the alluvial fans of the 

 arid regions at a distance of two or three miles from their source, to 

 show that the movement of large boulders may take place under sub- 

 aerial conditions ; he cites the absence of ice-borne boulders among 

 the finer strata of the Newark deposits ; and he argues a relatively 

 warm, not a cold climate, from the prevailingly red color of the for- 

 mation and from the character of the fossils. Emerson has detected 

 large boulders in certain basal beds of the sandstones in Northern Mas- 

 sachusetts, demonstrably close to their source, and not in the least 

 indicative of glacial transportation. Indeed, to conclude that glacial 

 action occurred at sea level during the period of Newark deposition 

 simply from the coarse nature of certain marginal conglomerates, is to 

 adopt an open alternative instead of a closed demonstration as a guide 

 to belief. 



Another line of evidence may be introduced against Fountaine's 

 argument that the Newark conglomerates of Virginia were derived from 

 glaciers which descended from the Appalachian mountains of that time. 

 Local glaciers could originate in that latitude only on lofty mountains, 

 from which they might descend to sea level, much as those of New 

 Zealand do now. But the evidence gathered from the outline of the 

 under border of the Newark areas does not at all favor the idea that 

 they closely adjoined lofty mountains. If such had been the form of 

 the surface whose submergence allowed the accumulation of the Newark 

 sediments, their under border must have been extremely irregular; 

 the Newark waters must have rounded many a bold promontory and 

 penetrated many a deep bay. The basal sediments accumulated along 

 so sinuous a water margin should now show some indication of these 

 promontories and bays. They should be distributed much in the way 

 that the Permian breccias of Wales lie around their once buried and 

 now resurrected mountains, and thus show their origin on an 

 extremely irregular coast. But as far as the basal beds of the Newark 

 system have been studied out, they do not indicate that the surface on 

 which they lie possessed any great relief at the time of their deposition. 

 Whatever deformation it had previously suffered, whatever mountain- 

 ous heights this deformation produced, the action of erosion had in 

 pre-Newark time carried away enough material to some unknown goal 



