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In like manner gneiss and mica-schist may be nothing more than altered micaceous and argillaceous sandstones, granular quartz may have been derived from siliceous sandstone, and compact quartz from the same materials.
Below this are the plumbago and clay slates of Punkabaree, which alternate with beds of mica-schist with garnets, and appear to repose immediately upon the carboniferous strata and sandstone; but there is much disturbance at the junction.
But if we investigate different mountain chains, we find gneiss, mica-schist, hornblende-schist, chlorite-schist, hypogene limestone, and other rocks, succeeding each other, and alternating with each other in every possible order.
Hence all the rocks on this line of coast belong to one series, and insensibly vary from an altered feldspathic clay-slate into largely foliated, true mica-schist.
When I separated the pebbles of quartz, which were never striated, and those of granite, mica-schist, and diorite, which do not often exhibit glacial markings, and confined my attention to the serpentine alone I found no less than nineteen in twenty of the whole number polished and scratched; whereas in the terminal moraines of some modern glaciers, where the materials have travelled not more than 10 or 15, instead of 100 miles, scarce one in twenty even of the serpentine pebbles exhibit glacial polish and striation.
Near rocks of dazzling mica-schist was a miserable hut with a patch of buckwheat reaching to the stream. A man standing amidst the white flowers of the late-sown crop said, in answer to my questioning, that I could not possibly reach the village of Port-Dieu without walking upon the line and through the tunnels.
The fact often referred to in this chapter, of the foliation and the so- called strata in the metamorphic series, that is, the alternating masses of different varieties of gneiss, mica-schist, and hornblende-slate, etc., -being parallel to each other, at first appears quite opposed to the view, that the folia have no relation to the planes of original deposition.
The entire southern part, and the whole western coast, consists of mica-schist, which likewise is seen in the ravines of the interior. The central mountains rise to a height of 3,000 feet, and are said to be partly formed of granite and greenstone: there are two small volcanic districts.
So, if a man is going to build a boat, you might show him a collection of fossils, and discourse to him of the gneiss system, the mica-schist system, or talk of the atomic theory and protoplasms. Such knowledge would help to enlarge his views, extend his range of vision, and strengthen his memory, but would not help the man to build his boat.
It is probable that, had they been subjected to more intense Plutonic action, they would have been transformed into hornblende- schist, foliated chlorite-schist, scaly talcose-schist, mica-schist, or other more perfectly crystalline rocks, such as are usually associated with gneiss.
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