GLACIAL SUCCESSION IN CENTRAL LUNENBURG PREST. 169 



back it ? If we choose the latter as the cause of many of our 

 phenomena, we have the following succession of events. They 

 are numbered to accord with the supposed corresponding 

 deposits in the sections before given : 



1. General glacial epoch : Nova Scotia covered by a conti- 

 nental glacier which masked the country with an enormous 

 thickness of glacial debris of northern origin. 



2. Interglacial epoch of considerable length, during which 

 the pre-glacial valley of the Lahave was re-excavated to its 

 former depth, immense kames formed, and the remaining drift 

 oxidized more completely than any recent deposit. As a proof 

 of the enormous length of this interglacial epoch, nothing is 

 more convincing th^n the complete oxidization of these under- 

 lying deposits compared to the relatively slight change of a like 

 nature wrought in ordinary boulder clay of a more recent date. 

 The development of the Pithecanthropus erectus, with its 1000 

 cubic centimetre skull, is no surprise when such lengthened 

 periods are dealt with (pardon this digression.) 



3. A glacial epoch of shorter duration and less intense 

 action. This was probably divided into two lesser epochs near 

 the southern limit of its extension by a slight recession, and 

 thus gave rise to the upper and lower deposits of Blockhouse. 

 There was probably a repetition of such recessions and advances, 

 until the general ice sheet dwindled to a local ice field and finally 

 disappeared. 



4. A local recession at Blockhouse, as mentioned above, 

 during which a few beds of clay, sand, and bog iron were 

 deposited. 



5. A slight re-advance of glaciers on courses governed by 

 the local surface contour. In its bearing on the deposition of 

 the auriferous drift at Blockhouse, this re-advance was adequate 

 to a separate glacial epoch, and from a miner's stand-point will 

 have to be treated as such. 



6. Final retreat of glaciers, formation of river terraces 

 and general elevation of the country, during which our now 

 submarine river channels were excavated. 



