Neuropteris acutifolia, et angustifolia, et flexuosa, et macrophylla, et oblongata.
Pecopteris abbreviata, et arborescens, et cristata, et dentata, et Serlii.
Sigillaria contracta, et elongata, et mammillaris, et ornata, et reniformis.
Sphenophyllum fimbriatum, et Schlotheimii, et truncatum.
Sphenopteris Hibbertii, et macilenta.
Stigmaria ficoides.
Ulodendron Lindleyanum, et Lucasii.
The same variations in thickness as well as “faults” which have been detected in the lower coal seams, occur in the middle measures, although they do not in any case assume the same magnitude as the “Horse” in the Coleford High Delf.
The heart of the Forest basin is well defined by its forming a slightly varied plateau, containing the inferior and comparatively unimportant seams of Woor Green coal, situated of course nearer to the surface than the other veins, but as yet only sparingly worked, and not accurately defined in its outcrop. The highest elevations in this portion of the district are:—Surridge, 658 feet; Speech-house, 581 feet; St. Paul’s, Park End, 270 feet. The combined vertical thickness of the entire formation, descending from the top surface to the old red sandstone, is calculated by Mr. D. Williams at 2,765 feet, an opinion which is corroborated by Mr. Atkinson’s highly interesting sections based on his practical acquaintance with the mining operations of the Forest.
Mr. Mushet obtained by analysis the following percentage of carbon in the various descriptions of coal, viz.:—