Davis — Framework of the Earth. 229 



outgrown the space allotted to it ; hence only part of it 

 appeared in the dictionary: the completed statement, 

 still set up in the narrow form of dictionary columns, 

 came out in three small but thick volumes in 1852. The 

 system thus set forth now seems to have been more 

 illuminated by lamplight than by daylight. In the very 

 country where the pentagonal network longest held 

 ground under the authoritative teaching of its inventor, 

 it has now been completely replaced by the non-geo- 

 metrical and highly irregular mechanistic system, as it 

 may be called, which the great Austrian geologist has 

 developed, and which many French geologists have in 

 recent years done much to support. 



It is not the intention of this article to attempt a review 

 of Suess's conclusions; their general nature may be 

 apprehended from a chapter in the final part of the work 

 entitled "Analyses," in which the chief results gained 

 in the previous volumes are summed up, especially with 

 regard to the leading structural elements of the earth, 

 among which, although they are of different nature and 

 area, instructive comparisons may be instituted. The 

 chief and best known of these are : Laurentia in north- 

 ern America, a vast area of ancient rocks on which 

 Cambrian strata still lie horizontal and on which no 

 Mesozoic strata were deposited until the time of the 

 great Cretaceous transgression. (2) The Caledonids, a 

 belt of pre-Devonian folding, which stretches from north- 

 ern Ireland across Scotland and western Scandinavia to 

 Spitzbergen. (3) The vast Eurasian edifice, the greatest 

 of all the elements, with its medial area of "Angara" 

 in northern Asia, like Laurentia in consisting of ancient 

 rocks on which horizontal Cambrian strata lie uncon- 

 f ormably ; this medial area being bordered on the south 

 by great mountain chains of medieval or modern origin 

 which frequently show a loop-like arrangement, and which 

 continue so far as to envelop the northern hemisphere; 

 for one wing of the mountain chains stretches far east- 

 ward around the border of the north Pacific into the 

 Eocky Mountains of northwest America, and another 

 stretches far westward, possibly as a once continuous 

 land mass, across the Atlantic into the Appalachian sys- 

 tem; thus our Laurentia is enclosed on the southwest 

 and southeast by extensions of the Angaran mountain 

 border. (4) The Gondwana continent, originally extend- 



Am. Jour. Sci.— Fourth Series, Vol. XLVIII, No. 285— September, 1919. 

 16 



