456 A. F. BUDDINGTON 



a chloritized granite gneiss is overlain by Cryptozoan limestone 

 beds of Lower Cambrian age. Just west of Manuels three exposures 

 of the unconformable relations are presented. At the first locality 

 Kmestone rests unconformably on granite and on a rhyolite dike 

 in the granite. A shale bed of Cambrian age overlaps the limestone 

 and also rests directly on the granite and contains pebbles of it. 

 A near-by conglomeratic limestone consists almost entirely of 

 cobbles of rhyolite similar to the rock of the rhyolite dike. At the 

 second locality a deep-fissure deposit of conglomeratic limestone 

 with pebbles of the country rock occurs in diabase. At the third 

 locality a Lower Cambrian conglomeratic limestone carrying 

 Hyolithes and Coleoloides rests on dark-red rhyolite, the pebbles 

 consisting almost entirely of the underlying rock. Again, in the 

 bed of Manuels Brook a coarse conglomerate rests unconformably 

 on volcanics and on a granite dike intrusive in the volcanics. The 

 conglomerate is of Lower Cambrian age and consists of cobbles and 

 bowlders of the underlying granite and volcanics. 



On Trinity Bay, along Smith and Random sounds, the Lower 

 Cambrian, of older age than that on Conception Bay, rests discon- 

 formably on beds of the Random formation in the trough of a 

 syncline. The Random may be either conformable or disconform- 

 able with the Signal Hill series. In either case the Lower Cambrian 

 must be unconformable with the Signal Hill series and all lower 

 formations, since it must necessarily have transgressed all the later 

 pre-Cambrian formations in passing from its disconformable posi- 

 tion on the Random, the youngest formation of the pre-Cambrian, 

 in the trough of a syncline, across the flank of an anticline on to the 

 lowest later pre-Cambrian formation, the Avondale volcanics, on 

 the core of an anticline in Conception Bay. 



AVONDALE VOLCANICS 



Howley (1907) mapped a series of rocks which he called 

 Huronian and described "as composed of mixed igneous and 

 aqueous deposits in a highly metamorphosed condition." Parallel 

 to their trend they are mapped by Howley as outcropping for a 

 distance of about two hundred miles in a north-northeast-south- 

 southwest direction, being submerged beneath the sea at each end. 



