106 SIDNEY POWERS 



strip of Carboniferous conglomerates and shales forming a high, 

 rugged topography from Lower to Upper Economy, as shown in 

 Figs. 19 and 24, rising 250 feet, or more, from the lowland on the 

 south. The relation of the Triassic to the older rocks, as seen 

 along the shore, is a fault west of Carr Brook, and an unconformity 

 near Lower Economy (Fig. 25). 



At the fault, the Triassic consists of very calcareous sandstones, 

 containing conglomerate lenses and cross-bedding. Calcite has 

 been introduced into the sandstone, forming dark-red concretions. 



The unconformity near Lower Economy shows a basal con- 

 glomerate composed of subangular pebbles 1 to 3 inches in length, 

 resting on upturned and leveled Carboniferous red shale. The 

 shale within a foot of the contact is weathered into a clay, but this 



Fig. 22. — The shore section along Gerrish Mountain, as seen from the eastern 

 end of Moose Island. The Triassic sandstone, at the left, is faulted against a mass of 

 agglomerate overlain by a capping of sandstone. The agglomerate is probably faulted 

 against the dike of diabase, which has fed the basalt flow which caps the cliffs on the 

 right. At the base of this flow is a bed of green ash, and beneath this is normal 

 Triassic sandstone, with some shale. 



weathering is of recent date. The basal Triassic conglomerate 

 pebbles consist of slate, schist, quartz, and igneous rocks from the 

 Cobequid Mountains. Above the basal conglomerate, which is 

 25 feet thick, are interbedded sandstones and conglomerates as 

 seen in Fig. 26. It is 1,200 feet stratigraphically between the basal 

 unconformity and the Gerrish Mountain basalt flow. 



From Economy to Truro, Minas Basin is fronted by a compara- 

 tively low land underlain by practically horizontal Triassic sand- 

 stones, above which, in places, are Pleistocene gravels. 



The northern contact is of importance because there is a ques- 

 tion whether there is a fault or an unconformity. The exposures 

 are confined to the steam valleys, and are quite unsatisfactory. 

 It may be briefly stated that the relation is probably a fault as far 

 as Chiganois River, with another fault from there to North River, 



