[MATTHEW] GEOLOGICAL CYCLES IN MARITIME PROVINCES 141 



The Permian Sub-cycle. 



The rocks of this period cover but a limited area in the continental 

 part of Acadia, though they are largely spread in Prince Edward Island. 

 Much of the phenomena of this time are beyond our observation, as the 

 sediments of the period are, to a great extent, concealed beneath the 

 waters of the Gulf of St. Lawrence. 



The terrane begins witli a conglomerate, the New Glasgow con- 

 glomerate, well shown near Pictou, in Nova Scotia, and extending 

 thence along the northern shores of Nova Scotia into New Brunswick. 

 Mr. Fletcher's description of the strata of this terrane recalls in many 

 respects the conditions and aspect of the Upper Devonian rocks in this 

 region. The great preponderance of red shales and red sandstones, 

 the prevalence of plant remains in many beds, the occasional presence 

 of nodular or " botrj^oidal " limestones, all suggest deposits which may 

 have been laid down on broad flat plains in a comparatively dry climate. 

 They suggest that the carboniferous plain which previously had a tri- 

 angular form with its apex at Oromocto lake was now reduced in area 

 and confined to a tract including the present southern shallows of the 

 Gulf of St. Lawrenoe and the borders of Nova Scotia and New Bruns- 

 wick adjacent; on this extended plain, with rivers entering it from the 

 west and south, would have been spread out the red sands and muds 

 Avhich now form the bulk of the Pennian deposits of Acadia. 



Of the last three terranes it would \seem that the coal measures is 

 the only one which may be considered in view of the variety of sedi- 

 mentation to rise to the dignity of a cycle. The Lower Carboniferous 

 began with a sudden depression omitting the usual preliminary stages, 

 and the Permian is so uniform as to show no special middle period of 

 unusual depression. 



The whole of these later stages, from the Lower Devonian onward, 

 (except the Lower Carboniferous) are devoid of true continuous marine 

 sedimentation, and the irregularity of the cycles may be ascribed to 

 this fact, as the sea only occasionally invaded the land. 



The Triassic Cycle. 



The period of the Trias (or the Jura-Trias, for there are as yet 

 no data for determining the exact time limit of this cycle) introduced 

 more violent geological changes than had been seen in this region since 

 Devonian time. 



The vicinity of the Bay of Fundy was the area where the geological 

 phenomena of the period are best shown; and the depth of its waters 

 to-day is one of the criteria which marks the violence of the volcanic 



