108 ROYAL SOCIETY OF CANADA 



Strait, in the counties of Cumberland, Colchester and Pictou. These 

 unconformities evidently represent periods of elevation extending for 

 long intervals of time, in which the rocks of the Millstone grit division 

 were raised above sea-level and again became submerged at the begin- 

 ning of upper Carboniferous time. So also about the shores of Minas 

 basin, the soft red beds of Triassic age were deposited upon Devonian or 

 lower Carboniferous sediments, showing in this case even greater inter- 

 vals or gaps in the deposition of the Carboniferous strata. It is evident, 

 therefore, that these gaps or breaks, sometimes of great extent, in the 

 order of deposition, cannot be assigned to any one period in the earth's 

 history, but have affected many formations, ranging from the earliest 

 of the sedimentary rocks to those which in eastern Canada are regarded 

 as the most recent in order of time. 



