54 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [June 16, 
mass, consisting of beds which appear to dip conformably with the 
underlying sandstones. At its western side it abuts against greatly 
disturbed red sandstones succeeded by other red sandstones dippmg 
to the southward, and extending as far as Swan Creek. 
On the west side of Swan Creek, the soft red and variegated sand- 
stones are seen to dip to the north at an angle of 30°, and are under- 
laid by a bed of trap conglomerate, which rests against disturbed 
strata of a composition different from any previously occurrmg in this 
section. They consist of lammated, compact and brecciated grey 
limestone, a bed of white gypsum, hard reddish purple and grey 
marls and sandstones, some of them with disseminated crystals of 
specular iron ore. I saw no fossils m these beds, but as they are 
identical i mineral character with some parts of the gypsiferous 
member of the carboniferous group, and have evidently been disturbed 
and altered before the deposition of the overlymg trap conglomerate 
and red sandstone, I have no doubt that they belong to the carboni- 
ferous system, the sandstones and shales of which, with some trappean 
rocks, occupy the cliff between this place and Partridge Island five 
and a half miles distant. ‘The new red sandstone in the vicinity of 
Swan Creek appears to form a small synclinal trough, occupymg an 
indentation in the carboniferous rocks, and probably extending only 
a short distance westward of the mouth of the creek. The two 
islands near Swan Creek are detached masses of trap, resting on or 
rising through red sandstones, which at low tide are seen to extend 
between them and the shore. The red sandstone and trap, oecurrmg 
in the section between Five Islands and Swan Creek, appears to be a 
very narrow band, extending parallel to the coast ; and as the section 
is nearly in the general direction of the strike of the formation, it is 
probable that some of the trappean masses above-described are por- 
tions of beds disconnected by faults and denudation. 
Partridge Island consists above of black crystalline trap, with a 
vertical columnar structure. On the western side, this is seen to 
rest on a thick mass of amygdaloid and earthy and arenaceous tufa. 
Underlying these, at the north-western extremity of the island, are a 
few beds of soft red sandstone with greenish bands, dipping to the 
southward. The mainland opposite consists of vertical and hardened - 
dark-coloured sandstones and shales of the carboniferous system, 
containing Flabellaria, Ferns, and shells of a species of Modiola and of 
Unio. Vertical and contorted carboniferous strata occupy the coast 
section as far as Cape Sharp, three miles distant. This promontory 
consists of trap and underlying red sandstone, as at Partridge Island, 
except that trap conglomerate and breccia take the place of the finer 
tufaceous matter seen at the latter place. Westward of Cape Sharp, 
the coast consists chiefly of carboniferous rocks, with some isolated 
masses of trap, associated with red sandstone, in small patches. 
These I have not been able to examine. 
The compact trap occurrmg in the sections above-described, is a 
fine-grained crystalline augitic rock of a dark grey or blackish colour, 
and often with a rude columnar structure. The amygdaloid is of a 
grey colour, and its vesicles are usually filled with zeolitic matter. 
