REPORT OF THE DIRECTOR I914 131 



the east through a putative passageway across Appalachia, in 

 northern New Jersey. Paleogeography makes many tentative de- 

 mands of its followers. The writer could never visualize this 

 gateway and Professor Barrell, after long study, has hung over it 

 the sign : " Closed." 



The extent of Devonic intra-Appalachian vulcanism. Outside 

 the western hemisphere, volcanic activity was widespread during 

 the early Devonic. The interior Devonic basin of North America 

 has been regarded as almost devoid of such activities and, from 

 South America, we have no present knowledge of volcanic out- 

 flows in the sheet of Devonic sediments. The contrast in this regard 

 between the basins or intermontane channels of the northeast Ap- 

 palachians and those farther south is very marked. Rhyolitic ashes 

 and scoriae interlaminate the marine Lower Devonic of Dalhousie ; 

 volcanic dikes traverse the lower limestones on the Grande Greve 

 peninsula ; the Gaspe sandstone is cut in several places by such 

 dikes and the Bonaventure formation is locally overwhelmed by 

 lava outpours. New York and the interior region are not wholly 

 without such evidences — dikes of alnoite penetrate the Upper 

 Devonic near Ithaca, serpentinized peridotite forms dikes which 

 traverse the Siluric and Devonic about Syracuse ; dikes of like 

 character, in an extensive parallel series, cut the Ordovicic of the 

 Mohawk valley and may have penetrated, in all probability did, a 

 once overlying Devonic mantle. These dike intrusions, however, 

 are along preexistent fault or joint lines, all accessory to the orogenic 

 structure of the eastern mountains. In other forms than this, vul- 

 canism, it has been generally regarded, does not manifest itself in 

 these Devonic areas of the interior. 



Over the St Lawrence lowlands lying between Montreal and the 

 New York-Vermont boundary, is an array of volcanic stacks and 

 domes varying in size and effect from the most majestic in Mount 

 Royal, to the lesser ones at the south ; all of which have been termed 

 by Doctor Adams, the " Monteregian Hills." These are lavas in 

 various stages of differentiation but all have obviously penetrated 

 a great plain of Ordovicic (Lorraine) shales. There is, however, 

 a definite indication of the age of these intrusions presented by the 

 contact breccias known on St Helen island near Mount Royal, in 

 which are fragments bearing unquestionable Lower Devonic fossils ; 

 fixing thus the age of the lava intrusions as at least post-Lower 

 Devonic. These blocks in the breccia are the only known trace of 

 the Devonic in all this region, from the St Lawrence southward into 



