Vietnam or Thailand ? Vote for the TOP Country of the Week !
Updated: May 5, 2025
In some places I distinctly saw the white conglomerate and overlying beds inclined at from 25 to 30 degrees to the west, and at the bottom of the same mountain, the clay-slate and grauwacke inclined to the same point, but at an angle from 70 to 80 degrees: in one instance, the clay-slate dipped not only at a different angle, but to a different point from the overlying formation.
But these catastrophes, as we well know, do not imply that the land or sea of the disturbed region are rendered uninhabitable by living beings, and by no means indicate a state of things different from that witnessed in the ordinary course of nature. General Character of Metamorphic Rocks. Gneiss. Hornblende-schist. Serpentine. Mica-schist. Clay-slate. Quartzite. Chlorite-schist.
On this view the white conglomerates and the presently to be described tuffs and lavas are really unconformable to the main part of the clay-slate; and this, as we have seen, certainly is the case with the clay-stone lavas in the valley of Canota, at the western and opposite base of the range.
Relation between movements of subsidence and volcanic action. Pampean formation. Recent elevatory movements. Long-continued volcanic action in the Cordillera. Conclusion. I have already described the general nature of the rocks in the low country north of Valparaiso, consisting of granites, syenites, greenstones, and altered feldspathic clay-slate.
Bed 12, dull purplish or greenish or dark-grey, very compact and much indurated mudstone: estimated at 1,500 feet in thickness: in some parts this rock assumes the character of an imperfect coarse clay-slate; but viewed under a lens, the basis always has a mottled appearance, with the edges of the minute component particles blending together.
In the hills of pudding-stone in the neighborhood of Roxbury, we have quartz pebbles cut down to the same level with the softer paste in which they lie imbedded with pebbles of sandstone, clay-slate, gneiss, and limestone.
In this Sound, about fifty icebergs were seen at one time floating outwards, and one of them must have been at least 168 feet in total height. Some of the icebergs were loaded with blocks of no inconsiderable size, of granite and other rocks, different from the clay-slate of the surrounding mountains.
The actual junction between the granitic and clay-slate districts extends over a width of about two hundred yards, and consists of irregular masses and of numerous dikes of granite, entangled and surrounded by the clay- slate: most of the dikes range in a N.W. and S.E. line, parallel to the cleavage of the slate.
The cliff was from forty to fifty feet high and quite perpendicular, and had at its base a small slip of soil formed of the debris of a bed of clay-slate. From this narrow spot Dr.
The pebbles vary from minute ones to the size of a hen's egg, and even to that of half a man's head; they consist of paler varieties of porphyry than those found further northward, and there are fewer of the gallstone-yellow kind; pebbles of compact black clay-slate were here first observed.
Word Of The Day
Others Looking