CAMBRIAN ROCKS OF NOVA SCOTIA. — POOLE. 239 



question, has been very thorough, and the rock, strong and 

 durable, is in marked contrast to the rest of the superficial 

 drift classed with the Pleistocene which ordinarily about Hali- 

 fax shows little trace of cementation, although Mr. Prest found 

 interbedded bands of bog iron ore and cemented gravels in the 

 LaHave till. 



As to the time of deposition, the general impression among 

 observers has been that the formation as a distinct rock was 

 subsequent to the earliest period of the ice age, when the older 

 rocks were rubbed down, furrowed and scratched by the pas- 

 sage over them of stones in the grip of Pleistocene ice. Now 

 the object of these remarks is to ask for a reconsideration of 

 this generally accepted view, and offer reasons for thinking that 

 the age of the lowest of some of the deposits on the Cambrian 

 may belong to a period more remote than the Pleistocene — a 

 conclusion that would be very effective in a consideration of the 

 vast antiquity of the main physical features of this province. 



In composition much of the conglomerate appears to be 

 largely made up of fragments from the slate group of the 

 Cambrian. A granite pebble was found with some quartzite at 

 the Halifax Dockyard, but only a few well-worn pebbles and 

 email boulders of quartzite were detected in the conglomerate 

 on the Dartmouth shore. Very possibly the patches of con- 

 glomerate owe their preservation largely to their position on 

 the slates whence came the ferruginous cementing water, while 

 it may be that the original extensions of the same deposits on 

 the granite and quartzite, where there were no cementing 

 waters, more readily suffered erosion and were removed. This 

 point wants looking into, in order to read aright the full story 

 which this rock has to tell of past conditions. The few quartz- 

 ite stones that were noticed at Dartmouth were some three 

 hundred yards south from the edge of the quartzite group cross- 

 ing the Narrows, and being well water- worn contrasted with the 

 slate stones of the bottom portion of the deposit, which were 



