Volume 1
Geology, introductory, descriptive, & practical / By David Thomas Ansted.
- David T. Ansted
- Date:
- 1844
Licence: Public Domain Mark
Credit: Geology, introductory, descriptive, & practical / By David Thomas Ansted. Source: Wellcome Collection.
251/540 page 221
![sandstone and shale, with courses of ironstone, and is not to be distinguished in its lithological characters from the ordinary coal strata in our own country. The carboniferous series in Belgium is not easily made out, nor can it be understood without considerable pre- vious knowledge of the relations of the strata as they are exhibited in less obscure and less disturbed districts. The difficulties that stand in the way chiefly arise out of the enormous derangements of the strata, which are not only violently contorted, but often elevated through an angle greater than a right angle, and are thus actually inverted,* so that the basin-shaped depressions in which the coal occurs are twisted out of place, and the whole Geology of the district apparently thrown into confu- sion. The only method of escaping from the difficulties thus introduced is to obtain horizontal sections, or ground plans of the various rocks in the district. In this way, by actually walking upon the edges of the strata, they may often be recognised as the same, in cases where vertical sections would appear to prove, that the newer beds were overlaid by a long series of more ancient * The simplest method of acquiring a true notion of the singular appearance and puzzling nature of these inversions of strata, is to consider such a case as that represented in the subjoined diagram, where a series of strata, originally horizontal, ] aS warts AT CHER MMT COAL BASINS OF BELGIUM. OBLIQUE BASINS. have been first disturbed and elevated by an igneous rock, and afterwards again by another eruption; the second disturbance acting chiefly between the two points of eruption and squeezing the beds laterally and with great violence. As a consequence of this pressure the shales and other strata have been con- torted into undulations, and puckered up just as a number of pieces of cloth are found to be if pressed vertically and at the same time squeezed laterally. The effect of this is represented in the diagram, and the axis is more or less inclined, according to the amount of disturbance.](https://iiif.wellcomecollection.org/image/b33279433_0001_0251.jp2/full/800%2C/0/default.jpg)
