Outlines of mineralogy and geology ... / [William Phillips].

  • William Phillips
Date:
1816
Catalogue details

Licence: Public Domain Mark

Credit: Outlines of mineralogy and geology ... / [William Phillips]. Source: Wellcome Collection.

    250/266 (page 220)
    ^20 and the chalk pass away beneath our feet, we haye no reasonable ground for concluding; but we are acquainted with the important geological facts, that the dip of the older rocks beneath the surface is much more highly inclined than that of the rocks of a middle age, and that the dip of the newer rocks becomes less and less inclined until we arrive at the newest, which lies nearly fiat. This difference of inclination in rocks of different ages, it has been already mentioned, has caused Werner to designate the more recent of them by the name of fioetz or fiat rocks, on account of their nearly fiat position. We are moreover further acquainted with the fact that the dip of the formations on the east of the lias, all of which are new er than it, is very inconsiderable ; so that the allow^ance we have made for the thickness of the strata between the bottom of the London clay and the surface of the coal may far exceed the truth, even though our allowance does not exceed one-twentieth of the distance which the outgoings of these strata occupy on the surface. The coal near Bristol dips towards the east, to use the miners’ phrase, 3 feet in 6 ; in other words, if the stratum of coal be followed down from its outgoing at the surface for 6 feet, a perpendicular line let down to that point from the surface would be found to be 3 feet in length. The characters of simple minerals, sometimes from mechanical admixture, sometimes from their chemical Composition, afibrd much scope for conjecture respecting their actual nature. But the diversity of appearance and even of the composition of a rock is sometimes so great, thatthe same description would by no means solBce for the whole of it. In granites and in the rocks be long-.