United States or Ghana ? Vote for the TOP Country of the Week !
Recent and Post-pliocene alluvial deposits. 1. Peat of the recent period. 2. Upland gravel of various kinds and periods, consisting in some places of unstratified boulder clay or glacial drift. 6.
These accumulations of rocky fragments and detrital matter are left at the termination of the glacier, where it melts in a confused heap called the "terminal moraine," which is unstratified, because all the blocks, large and small, as well as the sand and the finest mud, are carried to equal distances and quietly deposited in a confused mass without being subjected to the sorting power of running water, which would convey the finer materials farther than the coarser ones, and would produce, as the strength of the current varied from time to time in the same place, a stratified arrangement.
It shows that when some of these volcanoes were in action the valleys had already been eroded to their present depth. The tufaceous alluvium called trass, which has covered large areas in the Eifel, and choked up some valleys now partially re-excavated, is unstratified.
I have been led to this conclusion, from having so frequently observed that, where part of an unstratified mountain-mass resembled in mineralogical character the adjoining streams or strata, there were several other kinds of intrusive porphyries and andesitic rocks injected into the same point.
The boulders of Erreré do not rest on the stratified sandstone of the Serra, but are sunk in the unstratified mass of the clay. This should be remembered, as it will presently be seen that their position associates them with a later period than that of the mountain itself.
Near Ocotal this unstratified formation is nearly level, excepting where worn into deep gulches by the existing streams. The river has cut through it to a depth of over two hundred feet, and there are high precipices of it on both sides, similar to those near streams in the North of England that cut through thick beds of boulder clay.
The granite still remaining unstratified, becomes charged with green particles; and the talcose gneiss assumes a granitiform structure without losing its stratification."
Flint is a form of quartz, dull-lustered, usually gray or blackish in color, and opaque except on thinnest edges, where it is translucent. Over much of the northern states there is spread an unstratified stony clay called the drift. It often rests on sound rocks. It contains grains of sand, pebbles, and bowlders composed of many different minerals and rocks that the country rock cannot furnish.
The stones of the till are of many kinds, some having been plucked from the bed rock of the locality where they are found, and others having been brought from outside and often distant places. Land ice is the only agent known which can spread unstratified material in such extensive sheets. The FINE MATERIAL of the till comes from two different sources.
Unstratified rocks are those which were once, at a time more or less distant, in a melted state from intense heat, and which have since cooled into a half crystallized state; much the same as water, when growing colder, cools and crystallizes into ice. Strictly speaking, ice is rock, just as much as granite and sandstone are rock.