POSITIVE ELEMENTS 471 



em Illinois to the region of the Kankakee river . . . striking north- 

 erly through the western part of the lower peninsula of Michigan." It 

 also seems to have originated with the movements recorded in the Taconic 

 revolution, and this parma is often in connection with Missouria. 



Keewatinia. — See Laurentia. 



Keweenaw continent. — "Walcott 98 proposed this name in 1886 "for the 

 land that existed on the North American continental plateau at the hegin- 

 ning of Cambrian time/' "The name is now adopted for the continent 

 at the beginning of Cambrian time." 



Laurentia. — "The germ or nucleus of the future continent" (Dana). 99 

 "Great northern Nuclear" (Dana). 100 "Canadian shield" (Suess). 101 

 The western end of linger and fleer's, and Hull's (1885) Atlantis. The 

 name Laurentia was given by Williams. 102 



As early as 1856 Dana made the following statement in regard to 

 Laurentia : 



"The earliest spot or primal area will be that of the Azoic rocks, the first in 

 the geological series. Such an area extends from Northern New York and 

 Canada, northwest to the Arctic Ocean, lying between the line of small lakes 

 (Slave, Winnipeg, &c. ) and Hudson Bay. East and west, it dips under Silu- 

 rian strata, but it is itself free from superincumbent beds., [We now know 

 that the Ordovicic strata covered most of this area, but subsequently it ap- 

 pears that the sea did not again invade the western end of the shield.] . . . 

 It has apparently held its place with wonderful stability, for it is now, as 

 probably then, not far above the ocean's level. 



"This area is central to the continent ; and, what is of prominent interest, it 

 lies parallel to the Rocky mountains and the Pacific border, thus proving that 

 the greater force came from that direction in Azoic times, as well as when the 

 Rocky mountains were raised. Thus this first land, the germ or nucleus of the 

 future continent, bears in itself evidence with respect to the direction and 

 strength of the forces at work. The force coming from the Atlantic direction 

 has left comparatively small traces of its action at that time. Yet it has made 

 its mark in the Azoic stretching through Canada to Labrador, in the dip and 

 strike of the New York Azoic rocks, in the direction of the channel of the 

 Saint Lawrence and the northwest coast of Lake Superior, and probably also in 

 the triangular form of Hudson's Bay. Against this primal area, as a stand- 

 point, the uplifting agency operated, acting from two directions, the Atlantic 

 and the Pacific ; and the evolution of the continent took place through the con- 

 sequent vibrations of the crust, and the additions to this area thereby result- 

 ing" (Amer. Jour. Sci., vol. 22, 1856, 341, 342). 



98 Walcott: Twelfth Ann. Rep. U. S. Geological Survey. 1801, pp. 540. 541. 

 00 Dana : American Journal of Science, vol. 22, 1856. p. 342. 



100 Dana : Manual of Geology, 1874, p. 150. 



101 Suess: Antlitz der Erde. vol. 2, 1888, pp. 42-58. Translation in Sollas. vol. 2. 1001. 

 p. 254. Willis : Bull. Geological Society of America, vol. 18, 1007. pp. 303. 307. 



102 Williams : American Journal of Science, vol. 3. 1897, p. 304. 



XLIII — Bull. Geol. Soc. Am., Vol. 20, 1008 



