80 b 



GEOLOGICAL SURVEY OF CANADA. 



■Conglomerate 

 Point. 



Conglomerate 

 and lower 

 shales. 



The little promontory of which Conglomerate Point forms the south- 

 ern extremity, is composed of massive conglomerates and coarse 

 greenish-grey sandstones. The conglomerates hold fragments often 

 several inches, and sometimes two feet in diameter of felspathic and 

 dioritic rocks, with occasional pieces of grey sub-crystalline limestone, 

 and argillites and argillaceous limestone of dark colours. These are 

 evidently derived from the underlying Triassic formation, which has 

 been fully hardened at the time of the formation of the conglomerate. 

 Some pebbles of shaly argillite were found to contain fossils. 



The conglomerates join with the associated sandstones along undu- 

 lating lines, and the whole deposit evidences littoral conditions and the 

 action of currents. 



These conglomerates probably represent those of Subdivision B. at 

 Skidegate. They form a synclinal, of which the axis runs about N. 40° 

 W., but which appears to be cut off southward by a fault or faults, the 

 downthrow of which has been to the north. On the north side of the 

 conglomerates the lower shales go down with at least the volume above 

 assigned to them as a minimum thickness of the subdivision, but south 

 of the fault they reappear with a visible thickness of only 660 feet. 

 This thickness is exposed in a distance of about a quarter of a mile, 

 between the fault at Conglomerate Point and the outer side of the next 

 Unconformable point to the south-west. The southern edge of the lower shales is here 

 "triassic Wlth f° un d resting uncomformably on the flaggy argillites of the Triassic, 

 and as this is one of the places in which the unconformity between the 

 formations is most clearly shown, a short description of it maybe given. 

 The underlying series is exposed for a breadth of 300 feet, and is found 

 to be composed of regularly bedded flaggy argillites, becoming cal- 

 careous in some places. These have a general southward dip at an 

 angle of about 40°, but are somewhat contorted on a small scale. On 

 the north side, a concealed interval of 140 feet intervenes between 

 these and the lowest visible rocks of the overlying group, which are 

 then found with north-eastward dips at angles of 20° to 30°. They are 

 sandstones, generally soft and rather shaly, and spread over a wide area 

 on the beach, holding large and small calcareous nodules, which are 

 arranged parallel to the bedding, and in some cases contain abundance 

 of marine shells, of which a Lecla or Yoldia is the most abundant. The 

 nodules also hold obscure fragments of plants and calcified stems and 

 twigs of wood, while in the sandstones similar woody fragments have 

 been converted into true coal. This is in some cases evidently in the 

 form of branches or small trunks of trees, but is also found in rounded 

 masses, which, it is supposed, may have been derived from partly con- 

 solidated peaty beds of nearly contemporaneous origin. 



