Science-gossip . ro- eastern districts, where also perched blocks andmorainic mounds both testify to the effects of theGlacial period here. Along the eastern seaboard isa narrow tract in which Middle Lias (400 to 500feet), Lower (120 feet), Middle (400 feet), and UpperOolites (1,000 feet), extend from Golspie to theOrd of Caithness. The shales and sandstones ofthe Lias are full of plant remains, sometimesforming thin layers of vegetable matter. It is,however, the contents of the succeeding LowerOolite which have rendered these Secondary bedsfamous. The shales become increasingly car-bonaceous,
Science-gossip . ro- eastern districts, where also perched blocks andmorainic mounds both testify to the effects of theGlacial period here. Along the eastern seaboard isa narrow tract in which Middle Lias (400 to 500feet), Lower (120 feet), Middle (400 feet), and UpperOolites (1,000 feet), extend from Golspie to theOrd of Caithness. The shales and sandstones ofthe Lias are full of plant remains, sometimesforming thin layers of vegetable matter. It is,however, the contents of the succeeding LowerOolite which have rendered these Secondary bedsfamous. The shales become increasingly car-bonaceous, until finally the coal-seam of Brorais reached at their summit. Mr. Cadell states thatits existence was known as early as 1529. Themaximum thickness of the seam is 3J feet, and isdivided into two parts by a layer of iron pyritesabout six inches thick. In places it seems to bemade up of the crushed stems of Equisetitescolwnnavis, and, unlike the coal-measure seams,is made up of drifted vegetable remains, spread ~. Peak of Suilven, with Ice-worn Gneiss in Front.(From Cadells Geology and Scenery of Sutherland.) versy over the age of the Eastern Schists, the mainconclusions are shown in pleasing style. By thekindness of the publishers, we are enabled toreproduce two of the many excellent illustrationswhich are to be found in the book. The firstrepresents the peak of Suilven or the SugarLoaf, composed of horizontal courses of TorridonSandstone (pre-Cambrian) and standing like agiant sentinel in a heaving sea of gneiss. It is about2,400 feet high. The conglomerates and brecciasof this formation rest immediately upon theArchaean gneiss, passing up into grits and fine-grained sandstones. Evidence is not wanting ofeffects of the glacial plough in Sutherland. Onthe west the boulder-clay has been all but sweptaway, but the hummocky ice-worn gneiss of thewest is shown well in the illustration. The boulder-clay is only found in any quantity in the lower out as a true aqueous deposit over t
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Keywords: ., bookcentury1800, booksubjectnaturalhistory, booksubjectscience
