PRE-CAMBRIAN LITERATURE OF NORTH AMERICA 187 
Cambrian 
Pre-Cambrian (Beltian) 
Purcell series 
{ 
Erosion: early Cambrian uplift 
Gateway formation: (continental deposition), sand- 
stones, sandy argillites, some concretionary siliceous 
dolomite. Salt casts and ripple marks 
Purcell lava, Purcell sills: intrusion of gabbro accom- 
panied by outpouring of basalt over land surface 
Siyeh formation: (mainly continental, some possibly 
marine deposition), red, purple, and green mud- 
cracked argillites, ripple-marked sandstones, some 
limestones 
Kitchener formation: (continental and_ possibly 
marine deposition), calcareous argillites, argil- 
laceous quartzites ripple marked, mud-cracked,some 
limestones 
Creston formation: shallow water deposition, quartz- 
ites, argillaceous quartzites, mud cracks, and 
ripple marks 
Aldridge formation: argillaceous quartzites, some 
conglomerates 
