BY PROFESSOR STEPHENS 527 



Unionida?. I confess that the inspection of these rocks leads me 

 to guess at a more recent date for the formation than has been 

 proposed. But two or three hours are quite inadequate for 

 reasonable examination of so large a mass of fossils. Two or three 

 months would hardly be enough. 



It is not improbable however that these rocks upon the coast 

 line are the very uppermost beds of the series, and pass into quite 

 a different era from those inland. 



However this may be, it is certain that after a very long period 

 of subsidence, covering possibly, as hinted above, more than one 

 geological period, a reverse action commenced, and the whole basin 

 began to be eroded by the rivers which had filled it, and by the 

 rainfall which as century after century rolled past, and the land rose 

 more and more, found higher and higher elevations to work upon. 

 So by degrees and at last the surface was carved into the familiar 

 hill and dale, cliff and gully, which result from the erosion of 

 horizontally stratified rocks of different degrees of hardness. 



At some period during this emergence, and before the present 

 river system was elaborated a river now represented by the Orara 

 flowed from the south over a bed of quartz boulders and gravel. 

 These remain here or there, as in the older or upper drift on the 

 Orara range, as a capping to the hilltops which were originally 

 the valley bottoms along which the river ran. The boulders are 

 large enough to suggest floating ice as an aid in their transport. 

 But I do not know that the hypothesis is required. They must 

 indeed have travelled a'very considerable distance, from the head 

 of the Bellinger at least, and are not particularly well rounded. 

 Still as we cannot even guess what fall the stream which conveyed 

 them had from its source to their resting place, it is premature to 

 appeal to Ice. 



An example of this boulder or gravel bed may be seen on the 

 W. side of the river on the top of the ridge as you pass upwards 

 towards the west. These two drifts mark not exactly but roughly 

 the beo-innino; and the end of the Clarence River series. 



Meanwhile an abundant rainfall continued to erode the 

 eminences as the rivers deepened these channels, and the spoils of 



