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they are--but it is the condition they stand in that makes
When a gentleman finds his business more than he can manage, he takes a junior partner, because he knows a servant will not be equally in his interest. The mother who finds the education of her children too much for her own care, should take a partner and a friend, and consider her as such-a servant will never prosper the undertaking.
CONVERSATIONS ON GEOLOGY.
Adhesive Slate-Old Red Sandstone-Grit-Stone-Anomiæ
Encrinites. MRS. L.-We have much more to learn on the interesting subject of Fossils, but I do not mean to resume it now-it will perpetually recur as we proceed with the Transition and Secondary Strata ; and I shall then have occasion to present you with many more specimens. Having in a former conversation given you as much information as we bave, respecting the origin of the next class of Rocks, I may now proceed to show you what they are. But we have already encroached upon this new ground-for of the Transition Rocks, or those Secondary and Stratified Rocks, that repose immediately on the Primary, Clay Slate is among the first, and that I have already described to you.
ANNE. I remember it. You called it Argillaceous Schiste, and described it as the common Slate of which we know so well the appearance and utility.
MRS. L.--I think we left nothing to be said upon the subject. This Slate contains no organic remains, except the frequent impressions of vegetables, and sometimes of shells. Here is a specimen of Slate I
think you have not seen. Fig. 1. Plate 12. It is called Adhesive Slate, because it adheres strongly to the tongue. The Clay Slate often contains small veins of Tin.
ANNE.- Are the substances of this new Class as numerous as those of the Primary?
Mrs. L.-In the detail they are numerous--but M'Culloch considers them to be altogether but of three Species-Sandstones, Limestones, and Slate: other Geologists may reckon more, by making different arrangements of the Species. In their important contents these Strata become highly interesting. The next we shall speak of, is the Red Sandstone. When it lies upon Argillaceous Schiste, in a conformable or parallel position, we can find no exact line between them. The Slate becomes coarse and filled with fragments of Sand, producing the substance called Grauwache, which I have already shown you. Here is a specimen of what is called the Old Red Sandstone, because it lies the lowest. Fig. 2.
ANNE.-Of what is it composed?
MRS. L.-Evidently of the waste and ruin of the preceding Rocks. You see it has nothing of a crystalline appearance, but that of detached particles cemented together: and it is always found to contain most of the Primary substance, in contact with which it happens to lie. When these fragments are of the usual size of sand, they form the fine Sandstones—when larger, they produce what are called Grit-stones, and Conglomerates or Breccias. The Geologist calls all these Sandstones the Mineralogist distinguishes them with those different names. Here is a specimen of Coarse Grit. Fig. 3.
MA'T.-Sandstones are not in general very hard, I think.
MRS. L.-"In the finer Sandstones, the adhesion of the parts is sometimes slight; and the rock is therefore of a feeble textare. In others, the adhesion is very firm, although it is impossible to trace any particular
cementing medium by which the union of the parts is effected. But in some varieties, it is very apparent that the harder parts are united by the intervention of a general cementing medium or paste ; commonly consist ing of that ferruginous (Iron) Clay, to which the colour of the Rock is, in most cases, owing. In a few instances, this cement appears to be a Carbonate of Lime (Lime and Carbon); or else, by a mixture of the two, there is formed a sort of general basis, in which the harder parts are imbedded. Where a Stratum of Red Sandstone is formed of coarser materials, these are al. most invariably mixed with finer sand, and cemented in the same way. The sizes of the parts of which this Rock is formed, vary generally from the size of sand to a diameter of a few inches; but sometimes they attain the dimension of more than a foot. Sometimes, they are angular--sometimes rounded by friction and there are proofs of long-continued friction, as well as of distant transportation.
ANNE.This leaves no doubt that these Rocks were formed at a later period than the Primary.
MRS. L.---They must be so, since they are formed out of them, and that by no very short process. The Sandstones of course contain all the substances that compose the Primary Rocks--Quartz, Felspar, Clay, Mica, Lime, &c. : but it is very rarely that the whole are found together. The colour is what the name implies--varying from a bright ochre red, to a blackish purple. The most remarkable variety is a mixture of red and white, thence called Variegated Sandstone.
MAT.-The Sandstone Rocks, I suppose, are not
MRS. L.-"The Old Red Sandstone frequently forms mountains between two and three thousand feet above the sea level; in this respect, it yields only to the Transition and Primitive Chains of this Island, surpassing those of every other formation. Red Sandstone Rocks are seen in some parts of Britain in great beauty and