330 ROLLIN T. CHAMBERLIN 



different regions; and that is a crucial point. But from available 

 data it would seem that the deformation was in progress at some 

 points as early as the latter part of what has been classed as Silu- 

 rian, while it persisted at other points into what has been classed as 

 early Devonian. Even if the identifications are strictly decisive, 

 such a range of time for a major deformative movement would not 

 seem more than is to be expected under the hypothesis of a genetic 

 relationship between the movements in widely separated quarters 

 of the globe, for absolute simultaneity is improbable. The critical 

 question, however, lies between the weight that is to be given to 

 the identifications of the dividing line that has been fixed by 

 geologists in their local studies in the cases cited, and that which 

 may properly be given to the diastrophic movements when they 

 shall have received the critical attention that has been given to the 

 stratigraphic and paleontologic criteria. If a real discrepancy is 

 found ultimately, which class of evidence shall give way to the 

 other ? 



DEVONIDES 



In North America the most noteworthy orogenic disturbances 

 connected with the Devonian period occurred near its close in 

 eastern Quebec, New Brunswick, Maine, and perhaps also south- 

 westward through the tract of Appalachia which was rather dis- 

 posed toward upward movements during the Paleozoic. In the 

 Gaspe Peninsula of Quebec the Bonaventure conglomerate of late 

 Devonian, or early Mississippian, age was laid down unconformably 

 upon the vertical edges of the Silurian and Devonian strata about 

 Perce.^ The Devonian and older strata have been thrown into pro- 

 nounced folds of the Appalachian or Jura type, indicating that a 

 conspicuous mountain range was developed here after the deposi- 

 tion of these Devonian strata. The youngest formation included 

 in the folded mountains is the Gaspe sandstone, which has been 

 correlated by Clarke with the Hamilton of New York.^ The great 

 folds of Gaspe therefore arose some time between the late Hamilton 

 and the beginning of the Mississippian, with the evidence tending 



' J. M. Clarke, " Early Devonic History of New York and Eastern North America," 

 Mem. New York Mus., No. 9 (1908), 92-102. 

 => J. M. Clarke, op. cit., pp. 86-88. 



