. The Encyclopaedia Britannica; ... A dictionary of arts, sciences and general literature . LowerSilurian and perhaps the Upper Cambrian of the BritishIsles. It consists chiefly of slates and conglomiftates, withthe sandstones of the Chilhowee group above. Abovethese last are the Knox dolomite group, with its shalesand limestone more separated from the other two groupsand perhaps not exactly corresponding to any other recog-nized formations. The crystalline metamorphic rocks aremainly syenitic and micaceous gneiss, with micaceous, hom-blendic, and talcose schists. .Occasional small dykes o*dio
. The Encyclopaedia Britannica; ... A dictionary of arts, sciences and general literature . LowerSilurian and perhaps the Upper Cambrian of the BritishIsles. It consists chiefly of slates and conglomiftates, withthe sandstones of the Chilhowee group above. Abovethese last are the Knox dolomite group, with its shalesand limestone more separated from the other two groupsand perhaps not exactly corresponding to any other recog-nized formations. The crystalline metamorphic rocks aremainly syenitic and micaceous gneiss, with micaceous, hom-blendic, and talcose schists. .Occasional small dykes o*diorite, greenstone, and basalt traverse these rocks, some-times interstratified, but oftener breaking through thvin. 2. The rocks of the first division are tilted at Tf yy hi^angles; those of the second division, the eastern v&vley ofthe Tennessee, are fractured and distorted at nearly everyconceivable angle, and, in consequence, it is the edges ofthe uplifted strata which here form the siwfs^c. The stratat>Avo been culju awikV to form valle^rb, Ci l^^ft standing as. ^ wolciniTrof. C^ r TENNESSEE 177 riiges, giving the whole tract a deeply channelled character,the ridges consisting of sandstone and dolomite and thevalleys of friable schists. These all trend in the prevalentdirection of the Appalachian upheaval, from north-east tosouth-west. The rivers take the same directions, exceptwhen they break through transverse fissures in the ridges,or work round their terminations where they give way tothe outcroppiiig of other rocks; iii these cases the currentruns at right angles to their prevalent direction. All theseformations belong to the Silurian period, the oldest croppingout to the eastward, the later members appearing to thewestward. In some spots tha Subcarboniferous rockswhich once covered the entire valley have escaped theerosive action which swept the rest away. The wholedistrict is a valley of denudation which has been excavatedby the Tennessee and its tributaries,—som
Size: 1823px × 1370px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookidencyclopaedi, bookyear1902
