PRE-CAMBRIAN ROCKS OF NEWFOUNDLAND 



465 



conglomerates, both stratigraphically and geographically, inter- 

 bedded with the volcanic breccias, flows, and tuffs, is one of the most 

 cogent arguments for the subaerial origin of the volcanic series as a 

 whole; for both basalt and rhyolite conglomerates are associated 

 with and interbedded between completely angular basalt breccias 

 and well-rounded basalt conglomerates, and between similar angular 

 rhyolite breccias and well-rounded rhyolite conglomerates. In 

 some of the basalt conglomerate beds bowlders up to three feet or 



Fig. II. — Basalt volcanic conglomerate; Turks Gut, Colliers Bay, Conception 

 Bay. Photograph by G. v. I. 



more in diameter are not rare (Fig. 11). Such beds are in places 

 200 feet thick and grade upward or downward into sandstones or 

 tuffs. Some of the sandstone beds are cross-bedded and contain 

 abundant fragments of red shale constituting typical thon-gallen 

 beds. Others are ripple marked, but these features are rare. 



In the course of the work no reasons were found for assuming the 

 volcanics to have had other than an essentially subaerial origin. All 

 the structures and textures of the flows and the characters of the 

 associated volcanic products are compatible with such a hypothesis, 

 while the particular criteria pointing to such a conclusion are as 

 follows : 



