Clackmannan and Kinross . lyor stretch for hundreds of miles. One great fault beginsnear Stirling and may be traced in a line across Clack-mannan a little to the north of the Menstrie-to-Dollarroad. Beyond Dollar it appears to split into two is this fault that causes the igneous rocks of the Ochilsto come to an abrupt end in a great wall; and the rockson the southern side are estimated to have been displacedto a depth of at least io,ooo feet. One might readilysuppose that this enormous displacement was the directcause of the present difference in ele\ation ; in otherwords, that the
Clackmannan and Kinross . lyor stretch for hundreds of miles. One great fault beginsnear Stirling and may be traced in a line across Clack-mannan a little to the north of the Menstrie-to-Dollarroad. Beyond Dollar it appears to split into two is this fault that causes the igneous rocks of the Ochilsto come to an abrupt end in a great wall; and the rockson the southern side are estimated to have been displacedto a depth of at least io,ooo feet. One might readilysuppose that this enormous displacement was the directcause of the present difference in ele\ation ; in otherwords, that the step-like structure resulting from thethrow has persisted till to-day, but this has not been thecase. Both the igneous rocks of the present hills andthe carboniferous rocks of the modern plain were buriedunder hundreds, nay, thousands, of feet of later sedimen-tary deposits. These deposits have been gradually removedby the action of a stupendous denudation continuedthrough long ages, and it is only because the Ochils are. D. C. 18 CLACKMANNANSHIRE composed of the harder, more resistant igneous rocks thatthey stand to-day as a great northern wall overlookingand sheltering the worn-down plain of the more easilyremovable Carboniferous rocks. Nevertheless, we mustremember that, but for the fault, the igneous rocks, andtherefore the Ochils, would be continued further south-wards than they are, and neither the low plain of Clack-mannan nor its coalfield would be occupying their presentposition. This consideration gives weight to the con-tention that the great fracture was the most importantincident in the physical history of the shire. Another important event must also be noted. In thelatter part of the Cainozoic era, at a time which seems tohave immediately preceded the advent of man, the climateof these latitudes was intensely cold. Britain, as far southas the Thames, was at one period covered by a thicksheet of ice just as Greenland is now. Before the adxanceof this ice-sheet fro
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Keywords: ., bookcentury1900, bookdecade1910, bookidclackmannank, bookyear1915
