264 SIDNEY POWERS 



center of the flow was still liquid. The crust appears to have 

 become fissured, with some of the fissures reaching down to the still 

 molten rock, and other of the fissures having no great depth and 

 therefore being filled with quartz from above at a later stage. 



The structure of the flows is similar to that of all basalt flows. 

 The individual sheets are clearly distinguished by a relatively 

 thin amygdaloidal base and a relatively thick amygdaloidal top. 

 Flows composed entirely of amygdaloid were observed only at 

 Cape d'Or. The basalt is closely jointed and columnar joining 

 is frequently developed. The angle at which the columns and 

 planes between the sets of columns stand with respect to the vertical 

 and horizontal, respectively, indicates the dip of the flow. Faulting 

 in the sheets is frequently obscured by jointing. 



In North Mountain, from Cape Blomidon to Cape Split, and 

 along the Victoria Beach shore of Digby Gut, the thickness of the 

 flows may be estimated. A partial section is exposed at Sandy 

 Cove and at Freeport, on Long Island, and at Tiverton, on Brier 

 Island. In most of the sections the lowest flow is the thickest, 

 and at the top of the series are several thin flows. 



The section from Cape Blomidon to Cape Split shows two and 

 probably three flows, each with an estimated thickness of 150-300 

 feet. The top of the upper flow is exposed around the edge of Scots 

 Bay. It exhibits the small folds into which all the basalt flows 

 have been thrown. No other sections of the North Mountain 

 basalt are exposed until Digby Gut is reached, because the sea- 

 cliffs are low and expose only the upper flow or flows. 



At Victoria Beach the best section is found. There is some 

 doubt if the lower flow, as here estimated, is not composed of 

 two separate flows, but the microscopic examination of slides made 

 from the first exposures above and below the blank in the section 

 indicates a coarseness of grain which characterizes the center of a 

 thick flow. Erosion has probably removed several flows from the 

 top of the section. The section consists of: 



Top. Six flows 2-45 feet in thickness 160=*= feet 



Base. Main flow 600+ " 



The upper flows of the Victoria Beach section are absent from 

 the exposures at the end of Digby Neck. They have either been 



