50 BULLETIX OF THE JSTATURAL HISTORY SOCIETY. 



occurred in the region tliat can be compared to the vast 

 volcanic outbursts of the Iluronian, or tlie great pressure 

 and metamorphism of Devonian time. ISTevertheless, 

 there are proofs of some important movements along 

 these old fault lines. I should especially refer here to 

 that which bounds the south side of the Kingston hills, 

 and therefore the north side of the Kennebecasis valley. 



At this time the chain of hills between this valley 

 and that of Loch Lomond was of much greater height 

 than it now is, and iierhaijs was glacier-covered. From 

 these highlands a vast body of material was swept into 

 the valley below, and with the wash from other sources 

 accumulated to a depth of several thousand feet. At 

 the Joggins, in Xova Scotia, this Carboniferous forma- 

 tion, or terrain, has a thickness of fourteen thousand 

 feet, but in our region the thickness probably was not so 

 great. Whatever it was, however, the weak line of the 

 crust along the foot of the Kingston hills could not 

 sustain it, and it sank gradually its whole thickness along 

 this fault-line. Subsequent denudation scooped out a 

 good deal of these soft beds and produced the present 

 valley. 



There are indications that the great cross fault of the 

 Short Reach yielded somewhat at this time, sinking on 

 the East side : for while the Carboniferous deposits show 

 considerable bulk at Boar's Head and Kennebecasis 

 inland, they are hardly represented on the west side of the 

 river. The Cambrian sediments also east of this fault, in 

 the Long Reach valley, are much better developed, that is, 

 have been less eroded, than they have west of it. 



Estimates op Geological Time. 



As yet, however, there was no St. John river; the 

 chansres in, and denudation of the earth's surface which I 

 have endeavored to describe, were simply the stages which 



