Acadian Geology. [With] Suppl. Chapter (Paperback)

This historic book may have numerous typos, missing text, images, or index. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. 1855. Not illustrated. Excerpt: ... CHAPTER IX. THE CARBONIFEROUS SYSTEM-- Continued. CUMBERLAND COAL-FIELD, continued EXPLANATION OF JOGGINS SECTION EASTERN COAST OF CUMBERLAND USEFUL MINERALS OF CUMBERLAND--SOILS. In the last line but one from the bottom of the section, in the preceding chapter, the reader will observe the words " Underclay--stigmaria rootlets," and over this underclay is a small seam of coal. An underclay is technically the bed of clay which underlies a coal seam; but'it has now become a general term for a fossil soil, or a bed which once formed a terrestrial surface, and supported trees and other plants; because we generally find these coal underclays, like the subsoils of many modern peat-bogs, to contain roots and trunks of trees which aided in the accumulation of the vegetable matter of the coal. The underclay in question is accordingly penetrated by innumerable long rootlets, now in a coaly state, but retaining enough of their form to enable us to recognise them as belonging to a very peculiar root, the stigmaria, of very frequent occurrence in the coal-measures, and at one time supposed to have been a swamp plant of anomalous form, but now known to have been the root of an equally singular tree, the sigillaria, found in the same deposits (Fig. 9). The stigmaria has Fig. 9.--Bibs, Leaf Scars, arid Stigmaria Roots of Sigillaria--South Joggins. (rf) Stump with Roots, viewed from above. derived its name from the regularly arranged pits of spots left by its rootlets, which proceeded from it on all sides. The sigillaria has been named from the rows or leaf scars which extend up its trunk, which in some species is curiously ribbed or fluted. One of the most K remarkable peculiarities of the stigmaria rooted trees was the very regular arrangement of their roots, which ar...