260 



DBS C RIPTIV E C A T A L 0 G U E 



colour than the remainder of the rock. Most of the pebbles are amygdaloidal, with 

 the cells very much compressed, and filled with minerals. The cells in each pebble 

 have their long diameters parallel, but as they stand embedded, there is no uni- 

 formity between the direction of the cells of the different pebbles. The paste, 

 which is of an earthy character, is also very full of amygdules, compressed, and 

 having a uniformity of direction through the whole mass. In general appearance, 

 this specimen resembles the ordinary red shale conglomerates, and may be com- 

 pared with No. 201, and also Nos. 212, 259, 245, and 377. The elongated cells 

 in some of the enclosed pebbles are very much bent and contorted. Shows two 

 periods of action. 



629. Bears E. and W. Very ferruginous; colour, reddish gray, with a slight 

 greenish tint in some places. In the mass, fine granular ; in parts, crystalline ; the 

 more crystalline portions seeming to be near joints, and to be of but little depth. 

 The joints on weathered surfaces are very red. It is the rock described in 1848 as 

 " Columnar Rock." It is disposed to become globular in the mass, the diameter of 

 the globes being, occasionally, over twenty feet. In general structure, resembles 

 some of the N. 30° E. dikes ; and also bears some analogy to the volcanic grits, such 

 as are found in the neighbourhood of Kawimbash, Inaonani, and Two Island Rivers. 

 It is at some places an overlying rock, and is connected with the ferruginous grit- 

 beds. At some localities it appears to bear nearly N. and S. ; then N. 30° E., and 

 again E. and W. The difference in bearing I consider to be due to the different 

 directions in which the overlying beds are cut through and exposed. Very feebly 

 magnetic. The crystalline portion is made up of deep-red felspar, white felspar, 

 black hornblende, and peroxide of iron in lumps. A few quartz crystals are pro- 

 bably present, but it is not certain that the light-coloured mineral is not felspar. 

 (See No. 633.) The joints are lined with zeolites, either apopholite or stilbite, and 

 Heulandite (?). It has a tolerably straight fracture, though the surface is rather 

 uneven, and shows a tendency to be nodular. At Two Island River, and below, 

 this rock bears N. 30° E. 



630. Bears N. 30° E. Colour, greenish gray, with a reddish tint. Disintegrates 

 easily. Has an irregular, lumpy fracture. Heavy. So filled with green mineral, 

 that it is difficult to determine its composition. Structure, granular. The green 

 mineral which is so extensively disseminated through it is, probably, a variety of 

 talc. B. B. in the forceps loses its green colour, and becomes whitish, and with dif- 

 ficulty becomes rounded on the edges, with slight intumescence. With borax, fuses 

 to a clear glass, which, when cold, has a green tint, but is honey-yellow in the outer 

 flame ; — with salt of phosphorus, fuses to a white glass, with a silica skeleton. This 

 mineral has, probably, been mistaken for epidote, as well as for chlorite. It re- 

 sembles some varieties of the first in its fine granular and scaly disseminated state, 

 and the latter in large lumps. It is the mineral so extensively developed in the 

 volcanic grits, and which also occurs in thin veins in those rocks, associated with 

 calcareous spar and zeolites, as well as in the metamorphosed shales at some localities. 

 This rock is columnar, and overlying at many points on the Lake shore ; and the 

 dike to which it belongs has, probably, been one of the sources from which the volcanic 

 grits of Two Island River and the neighbourhood were derived. It does not affect 



