16 



made up of well rolled greenstone, occasionally granite and 

 slate, pebbles in a tufaceous cement also occur, but are not 

 common. 



The Hazelton tufaceous rocks, while probably mostly 

 deposited in shallow water, were occasionally built up on 

 land. North of Porphyry creek, a heavy band in the 

 series is made up of a confused mass of grey tuffs, which 

 grade into fine and coarse breccias holding numerous 

 rounded andesitic bombs often two feet (.6 m.) or more in 

 diameter. In portions of the region, especially from 

 Moricetown southward along the Hudson Bay mountains, 

 the fragmental volcanics are interbanded with rocks, 

 mostly green, occasionally red, andesites. 



No complete section across the basin occupied by the 

 Hazelton rocks has so far been made. The thickness is 

 consequently unknown, but it is estimated to exceed 4,000 

 feet (1,219 m -)- The beds and associated andesite sheets 

 are occasionally flat, or nearly so, for short distances, but 

 are usually compressed into open, more rarely close, folds, 

 and in places are strongly contorted. Faults are numerous, 

 and in most of the sections the rocks are fissured and tra- 

 versed by small calcspar veinlets. 



Large veins, important for their metalliferous contents, 

 chiefly silver-bearing galena, blende and chalcopyrite, occur 

 in the formation, Several of these are now being explored. 



The range in age of the Hazelton formation has not 

 been definitely established. Fossil plants occur in a number 

 of the shaly bands, and a few shells, usually imperfectly 

 preserved, have been collected at several points. These 

 indicate an age ranging from Jurassic up to Lower Cretace- 

 ous. 



Collections of fossils, made by W. W. Leach from the 

 upper part of the formation and reported on by Lawrence 

 Lambe, include the following specimens. 



Belemnites skidegatensis, Whiteaves. 



Nerinea maudensis, Whiteaves. 



Pleuromya papyracea, var. Carlottensis, Whiteaves. 



Astarte carlottensis, Whiteaves. 



Trigonia dawsoni, Whiteaves. 



Inoceramus concentricus , Parkinson. 



Pecten (entolium) lenticularis, Whiteaves. 



Pecten carlottensis, Whiteaves. 



Thracia semiplanata, Whiteaves. 



