Mr Jukes on the Geology of Newfoundland, 105 



to break them. It is frequently micaceous, and some portions 

 of it put on precisely the appearance of some mica-slate, 

 having a curved or wrinkled lamination, and being entirely 

 composed of scales of white silvery mica. Some slabs of this 

 shale are covered with singular markings in relief, at first 

 sight resembling the leaves and branches of small plants or 

 sea- weeds ; they are, however, I believe, concretionary, and not 

 organic. The softer parts of the shale frequently decompose 

 in situ into a dark brown earth, which lodges in the crevices 

 and on the ledges of the cliffs, and has precisely the appear- 

 ance of fine vegetable mould. The beds of gritstone which 

 occur at various intervals in this mass of shale, are univer- 

 sally fine-grained, grey internally, but weathering brown out- 

 side, generally thin-bedded, being rarely more than two feet 

 thick, and are divided by joints into sharp angular blocks. 

 These joints are almost invariably at right angles to each other, 

 and when also perpendicular to the beds, the blocks are of 

 course rectangular, and form good building stone. If not thus 

 naturally square, however, the stone will not readily admit of 

 being made so artificially, as it is of a brittle splintery charac- 

 ter. In the upper part of this formation, the shale is much 

 more abundant than the gritstone, which latter frequently oc- 

 curs in single beds, with regular intervals of shale between each ; 

 in the lower portion the beds of gritstone are more grouped 

 together, forming a thickness sometimes of 20 or 30 feet, and 

 the shale bears a less proportion to the stone than in the upper 

 part. The thickness of the whole formation must be consider- 

 able : but owing to the want of a continuous section, and other 

 difficulties, it must be left to conjecture. It cannot, however, 

 be so little as 600 feet. The Bell Isle shale and gritstone is 

 in some places seen to graduate or pass down by regular de- 

 grees into the next inferior, or that which I shall term the varie- 

 gated slate-formation. One formation is said to graduate down- 

 wards or upwards into another, when, at their junction, the beds 

 of each alternate the one with another, and no positive line of 

 separation can be drawn between the two. 



2. The Variegated Slate- Formation coii&\s>iBoid^md^%BO^TOQk^, 

 the most remarkable and abundant of which are some bright 

 red and greenish-grey slates. The upper part of this fonna- 



