NO. 2 PRE-CAMBRIAN ALGONKIAN ALGAL FLORA 83 



the Cordilleran sea on its eastern side and kept it out of the area 

 captured until the Upper Cambrian transgression came. From the 

 distribution of the Algonkian formations enumerated above there 

 must have been a revival of the broad geanticline of early Proter- 

 ozoic or late Archeozoic time that initiated the Rocky Mountain 

 line of uplift. The pre-Proterozoic geanticline was largely reduced 

 to base level before the first Cambrian transgression and the late 

 Proterozoic uplift resulted in relatively minor stratigraphic dis- 

 turbance. This is shown by the broad, comparatively low undula- 

 tions of the Algonkian formations subjected to erosion in Lower 

 and Middle Cambrian time. This late Proterozoic movement on the 

 eastern side of the Cordilleran geosyncline was not as great in the 

 Rocky Mountain area of Canada. This is proven by the Lower 

 Cambrian sea having deposited its sediments over the slightly dis- 

 turbed Algonkian Bow River series of Alberta. 



Coastal deposits. — By coastal or shelf sea deposits I mean the 

 deposits made along the coasts of the Pacific or other oceans either 

 in the open ocean or in bays or other bodies of water in immediate 

 connection with the ocean during Algonkian time. As far as known 

 to me there are no known marine continental fringing or slope de- 

 posits or faunas laid down in Algonkian time on or about any of the 

 continents or islands of the world. 



A great work of the future will be the finding of marine deposits 

 of Algonkian time and their contained life. 



Cambrian basal unconformity. — From the Robson Peak region of 

 British Columbia and Alberta to Arizona and southern California, a 

 distance of over i,ooo miles (i,6oo km.), clear evidence of a trans- 

 gressing Cambrian sea has been found in many localities, proving 

 conclusively that a general unconformity occurs here between the 

 Algonkian and Cambrian. This marked unconformity is the record 

 of the advancing, overlapping Cambrian sea. 



Climate. — The presence of great thicknesses of red sandstones 

 and shales in the Algonkian sections of the Grand Canyon and Belt 

 series of Montana suggests an arid and possibly a cold climate. 

 Opposed to this are the great limestone beds which indicate a fair 

 supply of water to form inland seas whose temperature was suffi- 

 ciently high to permit of an abundant growth of algae of a simple 

 type that served as the agency for the precipitation of vast quanti- 

 ties of calcareous matter. The only characterizing fossil of this 

 period, possibly of marine derivation, was a crustacean, Beltina 



