D B S CRIPTI V E CATALOGUE 



coloured particles sparingly disseminated through it. It also contains many pebbles 

 of red shale and green argillite. The rock breaks easily in the course of the cement, 

 the pebbles being liberated from their matrix without injury. It is a finer conglo- 

 merate than No. 441, few or none of the pebbles exceeding an inch in diameter. 

 Colour, reddish. 



443. Red slaty sandstone, in thin layers, with occasional yellow bands ; fine- 

 grained ; separates easily in the direction of the lamina?. Between some of the 

 layers thin bands of coarse gravel, well rounded and polished, and consisting mostly 

 of quartz and argillite. In the lower beds, as No. 441 is approached, the rock be- 

 comes more schistose, is of a greenish-gray colour, and consists, principally, of coarse 

 sand, and quartz-gravel and pebbles, with sulphuret of iron disseminated in frag- 

 ments and grains, all firmly cemented with clay and oxide of iron. The rock is 

 distinctly laminated, and separates easily in the direction of the laminse. The cross 

 fracture is rather smooth, passing through the pebbles and gravel-stones with as 

 much facility as through their matrix. In the lowest beds, near the junction of the 

 underlying rock, the various constituents are less firmly united, and the joints and 

 partings are of a dark iron-rust colour. 



444. Argillaceous sandstone — extremely fine-grained; colour, dark red; nume- 

 rous minute whitish dots disseminated through it. The upper surface is covered 

 with small protuberances, about an inch long and one-third of an inch wide, all 

 pointing in the same direction and overlapping one another, giving to the rock a 

 somewhat mailed appearance. 



445. Shaly sandstone — with pebbles and stripes of green argillaceous matter ; 

 very fine-grained. Resembles No. 674, but is whiter and unaltered. 



440. Siliceous shale — with thin layers of small pebbles or gravel, mostly of quartz 

 and slate ; no trap pebbles. 



447. Siliceous shale — colour, reddish to brown, with yellowish bands; fine- 

 grained. 



448. Argillaceous slate — colour, dark gray, with a reddish tint, becoming reddish 

 brown or chocolate-coloured on the weathered surfaces and in the joints. Some 

 portions of it are dark green on the surfaces of the joints, some of which are smooth, 

 and have a polished appearance ; there are numerous green stains, with a thin film 

 of talcose matter, and the structure of the rock presents a fibrous appearance. It 

 contains a few grains of oxide of iron. 



449. Argillaceous schist — colour, green; compact; contains numerous grains and 

 crystals of iron pyrites. It is not fissile, splitting only in the direction of the joints, 

 and then imperfectly. Between some of the joints there is a thin talcy coating. 

 The structure is fibrous throughout, so much so, as to lead to the supposition that 

 the constituents of the whole mass of rock, when in a plastic condition, have, in 

 consequence of a tilting force, slipped over one another, the harder grains of iron 

 pyrites leaving minute furrows and markings in the direction of the dip, which 

 being filled with the finer material, produced the fibrous structure alluded to. The 

 green colour is probably due to chlorite. 



450. Argillaceous slate — colour, dark blue and grayish blue ; very fissile, and 



