TRANSPORTATION OF BOWLDERS. 131 



The least distance from the most western of these Ijowlders to the margin 

 of the Archean belt is about 550 miles. I Other bowlders of Archean 

 origin which must have traveled nearly or quite as far occur in Kansas, 

 Missouri, and Il-linois, on the southwestern part of the drift-bearing area of 

 the United States. The method of transportation of all these is believed 

 by the writer to have Ijeen wholly by the slow currents of land ice. 



Dr. Robert Bell observes that the bowlders and pebbles of the drift 

 on the west coast of Hudson Bay, near the mouth of the Churchill, and on 

 the lower part of the Nelson, consist largely t)f rocks like those of the 

 opposite eastern coast of Hudson Bay, which is 500 miles distant.' But 

 the farthest known transportation of rock fragments- in the drift, recorded 

 in part by Dr. Bell, whose observations are supplemented by my own, is 

 from James Ba}- southwest to North Dakota and Minnesota. The rock 

 thus recognized is a "dark gray, granidar, siliceous felsite or graywacke, 

 * * * characterized by round spots, from the size of a pea to that of a 

 cricket ball or larger, of a lighter color than the rest of the rock, which 

 weather out into pits of the same form." It occurs in situ, as reported by 

 Dr. Bell, on Long Island, off Cape Jones, on the east coast of Hudson 

 Bay where it is narrowed to form James Bay, having there a southwest- 

 ward strike and probably continuing under the sea for some distance in 

 that dii-ection. He notes that the abundance of pebbles and bowlders of 

 this rock is the most remarkable feature of the drift on the west coast of 

 James Bay and along the Attawapishkat, Albany, and Kenogami rivers, 

 and that its fragments have been found by him as far west as Lonely Lake 

 and southward to Lake Superior.^ Farther to the southwest and south I 

 have observed fragments of it, usually only a few inches but in some 

 instances a foot or more in diameter, occurring very rarely in the drift in 

 the northeastern part of North Dakota, where the largest piece ever found 

 by me was about 30 miles south of the international boundary and 50 

 miles west of the Red River, and at numerous localities in Minnesota, 

 where it extends at least as far south as Steele County, 75 miles south of 

 St. Paul and 1,000 miles southwest of its outcrop north of James Bay. 



'Geol. Survey of Canada, Report of Progress for 1878-79, pp. 22, 23 C. 



^Geol. and Nat. Hist. Survey of Canada, Annual Report, new series, Vol. II, for 1886, p. 36 G. 



