HONEYMAN ON NOVA SCOTIAN GEOLOGY.. 347 



Devonian had altogether disappeared from Arisaig, and the series 

 became divided into Middle and Upper Silurian. 



In the part of the rocks of the Londonderry Mines correspond- 

 ing with the rocks exposed in our section^ I observed a supposed 

 lithological resemblance to the lower part of the Arisaig series, and 

 I designated it accordingly. I supposed that a higher portion 

 which is obscured in our section, was the Upper Arisaig. Regard- 

 ing it as possible that the band might have a wider geological range 

 than the Arisaig series, I still considered that a hio;her part or the 

 part next to the Carboniferous might be Devonian. In this case 

 the succession was regarded as unhrolzen. ISTow, however, as the 

 Devonian has almost, if not altogether disappeared from Nova 

 Scotian Geology, there is none found even to suppose its exist- 

 ence in the hand of our section. I expect that the farther exami- 

 nation of the section through the Cobequids will show that there is 

 every probability that the rocks under examination are of Middle 

 Silurian age. If this is the case, we have here another break in 

 succession, caused by the absence of the Devonian and the obscur- 

 ation of the Upper Silurian. 



The Upper Silurian of the other parts of the band has been 

 here denuded by the seas of the Lower Carboniferous period, and 

 overlapped by the conglomerate already described, the consolidated 

 shingle that accumulated on the wasted Upper Silurian strata. 1 

 observed nothing very marked in these Middle Silurian ( ?) strata. 

 Leaving these we enter upon another band of rocks, these arc 

 exposed in a series of beautiful sections to a width of 10,40() 

 feet. This series of rocks consists chiefly of diorites and quartzites. 

 The diorites are of different shades of green, and are crypto-crys ■ 

 talline ; the quartzites are often banded. Near the commencemen t 

 there is a gneissic stratum — farther on there is a bed or vein (^f 

 green calcite mixed with diorite. In one of the diorite sections 

 there is a thick vein of quartz. The lithological characteristics (.f 

 this band eflfectually separates it from the preceeding. There is n*) 

 part of the " Upper Arisaig Series," either at Arisaig or elsewhere, 

 that shows diorites similar to those of our section. The crystalliiiC 

 rocks of Arisaig or what I have elsewhere named the " Lower 

 Arisaig Series," alone exhibits diorites of similar character. 



