THE PROTEROZOIC ERA. 



211 



formity. 1 The general relations are shown in Fig. 

 few fossils have been found. 2 



Here, as in Montana, a 



In many of these localities the Proterozoic strata are associated with 

 Archean, but the details of their structure and relationships have not 

 been worked out in many places. Enough ; however, is known to render it 

 probable that many of these localities, as British Columbia, south- 

 western Montana, the Wasatch mountains, etc., were within the limits 

 of one geological province in the Proterozoic era. One of the features 



Fig. 86a. — Horizontally-bedded limestone, resting uneonformably on vertical beds of 

 Proterozoic Quartzite. Box Canyon, near Ouray, Colo. (R. T. Chamberlin.) 



common to much of this province is the conformity of the Proterozoic 

 strata beneath the Lower Cambrian. Within the province, a succes- 

 sion of formations and events as definite as those of the Lake Superior 

 province will probably be established when the several areas have 

 been studied with equal care; but the order established for this province 

 may not be very similar to that of others, since the sequence of events 

 in different provinces is not necessarily the same. 



1 Walcott, 14th Ann. Rept. U. S. Geol. Surv. and Bull. 30. U. S. Geol. Surv. 

 cott gives a three-fold division of the Algonkian. 

 'Walcott, Bull. Geol. Soc. Am., Vol. X. 



Wal- 



