NEWFOUNDLAND APPALACHIANS 



217 



indicate sharp uplift nearby, and the influx of much coarse clastic mate- 

 rial. Since Devonian plant fossils have been found in schistose strata in 

 the La Poile Bay area, it now seems probable that considerable of the 

 metamorphic rocks of central Newfoundland, aside from the batholiths, 

 will prove to be Devonian, and therefore a site of deposition during part 

 of Devonian time, at least. The sources of the Lower Devonian conglom- 

 erates and sandstones must have been along the Labrador coast on the 

 west and in an uplift through the Avalon peninsula on the east. 



A Caledonian orogeny in the White Bay and Notre Dame Bay region 

 has been suggested by Heyl ( 1937a ) in view of the lithologic similarity of 

 the Devonian and Mississippian there, in contrast to the Silurian and older 

 rocks. Also, the amount of deformaton of the Devonian and Carbonifer- 

 ous is less than that of the older beds. Schuchert and Dunbar ( 1934) note 

 that the Devonian sediments in the St. George Bay area are not strongly 

 deformed, except along Appalachian phase faults; they are apparently no 

 more disturbed than the Mississippian strata, and much less disturbed 

 than the Ordovician Humber Arm series. 



If an orogeny occurred in the White Bay and Notre Dame Bay region, 

 it is not unlikely that intrusive activity accompanied the deformation. 

 Some of the plutons of that region may, therefore, be Caledonian. They 

 may also have come in during the Devonian or at its close (Acadian). 

 Composite relations undoubtedly exist (Hayes, personal communication). 



Late Devonian Phase (Acadian Orogeny) 



Like the Taconic orogeny the Acadian is also illusive. Mississippian 

 elastics in themselves indicate sharp uplift nearby, and are generally be- 

 lieved to rest in angular relation on much deformed Ordovician strata 

 in western Newfoundland and in the White Bay and Notre Dame Bay 

 area, although the contact is seen in only a few places. The Mississippian 

 strata have suffered little metamorphism, however, and this sets them off 

 strikingly from the older deformed and altered rocks. Nowhere in New- 

 foundland has an angular unconformity yet been recorded between the 

 Mississippian and Devonian systems. Nevertheless, all workers in New- 

 foundland are aware of profound folding, batholithic intrusions, volcan- 

 ism, and metamoq:>hism that occurred sometime between the Ordovician 



and Mississippian; and since in two places the batholiths are found in- 

 truding the Lower Devonian series, it seems probable that many plutons, 

 similar in composition, are of the same age. The Acadian orogeny, pro- 

 ceeding through the late Devonian and into early Mississippian in the 

 Maritime Provinces and New England, was one of superior and wide- 

 spread proportions, and it is highly unlikely that Newfoundland, with its 

 similar geosynclinal assemblages and lying in the projection of the great 

 belt of orogeny, could have escaped it. 



Mississippian Phase 



The desposition of the Anguille conglomerates in the St. George Bay 

 area attended the upfaulting of the Long Range mass, and the same ac- 

 tivity is probably indicated by the Pilier conglomerate at Groais Island. 

 The Springdale elastics in the Notre Dame Bay area, if correctly dated, in- 

 dicate orogeny nearby. 



Early Pennsylvanian Phase 



The coarse and thick Barachois series of the St. George Bay area rests 

 conformably on the Lower Mississippian Codroy formation, but the 

 abrupt change from fine-grained, mottled red and green sandstones of the 

 Codroy to the coarse, red, feldspathic sandstone of the Barachois is strik- 

 ing. The influx of coarse red elastics signifies another sharp uplift, proba- 

 bly in the Labrador coast area. 



No other Pennsylvanian rocks are known in Newfoundland, and hence 

 nothing is known of the early Pennsylvanian disturbance outside the St. 

 George Bay area. 



Post-Early Pennsylvanian Phase (Appalachian Orogeny) 



The major fault zone that extends from the southwestern coast of New- 

 foundland in a northeasterly direction to Grand Lake, White Bay, and up 

 the east coast of the northern peninsula postdates the youngest sediments 

 of Newfoundland. These are the Barachois series of lower or middle Potts- 

 ville (Early Pennsylvanian) age. Relief features and escarpments in other 

 parts of the island trend northeasterly and parallel the western fault zone. 

 These in part may also be due to faults of the same phase. Betz ( 1943 ) 



