154. Genus ANOMOPTERIS, anomalous fern, Lign. 17.Frond deeply pinnated, leaflets very long, entire, linear; midrib distinct, and as long as the leaflet; veins simple, perpendicular to the median vein, and extending to the margin of the leaflet.

Leaves of large size, and probably belonged to an arborescent fern. Species, mougeotii. From new red sandstone, (132.) A portion is magnified to show the fructification.

155. Genus PECOPTERIS, embroidered fern, Lign. 18. Frond once, twice, or thrice pinnated; leaflets adhering by the base to the rachis; traversed by a strong midrib, which reaches the apex; veins once or twice dichotomous; and nearly perpendicular to the median vein. The species here figured is once pinnated. It is the species lonchitica, and is from the coal-shale, France.

This genus embraces by far the greatest proportion of the ferns, which have contributed to the formation of coal in all countries. The originals of many species were undoubtedly arborescent, and attained a very large size. Some fronds have been found, which were four feet wide, and of proportionate length. More than one hundred species have been determined. The species have been found in America and England, as well as in France.

156. Genus LONCHOPTERIS, spear-leafed fern, Lign. 19. Leaves many times pinnated; leaflets more or less adherent to each other at the base, and traversed by a midrib; secondary veins reticulated. Only a small portion of the frond is here figured. Species, Mantellii. Found in the Wealden, (137) This species seems to be a very deli

LIGN. 18.

Embroidered fern.

cate plant; for although indications of its presence are very general throughout the fine micaceous grits, and even the clays of Wealden, a perfect leaf is of rare occurrence. The upper figures are magnified leaflets, to show the reticulations.

157. Genus CLATHROPTERIS, latticed fern, Lign. 20. Frond deeply pinnatified, or cut into wings; leaflets elongated; midrib extending to the apex; veins simple, parallel, nearly perpendicular to the midrib, united by transverse bars, producing a quadrangular reticulation. Species, meniscoides. From the Wealden the original frond being one and a half feet long.

This genus was instituted by M. Brongniart, to include some fronds from the shale of Hoer, in Scamia, which resemble in structure, the foliage of the recent Polypodium quercifolium, a native of the East Indies.

158. The fronds of a great variety of ferns, as already stated, are every where to be found in coal fields; but an undoubted stem of any of this family is very rare. A few fossil stems, however, having all the characters of recent species, have been found, and are arranged under the following genus:

159. Genus CAULOPTERIS, fern stem, Lign. 21. Stem not channeled, marked with discoidal oblong or ovate scars, arranged longitudinally; vascular cicatrices numerous. Species, macrodiscus. From the coal fields.

The specimen figured is from the coal, and resembles the trunks of the living fern trees in its proportions, and in the number, disposition, and size of the scars of the leaf-stalks; but these markings differ from the recent, in the more lanceolate form and pointed terminations, and in their peculiarly striated surface.

160. Name from Sigillum, a seal, which alludes to the regular, and often beautiful, imprints on the stem.

What is said of the variety of fossil fern stems?

Among the most common, yet striking objects, says Mr. Mantell, that arrest the attention of a person who visits a coal mine for the first time, and examines the numerous vegetable relics that are profusely dispersed among the heaps of slate, coal and shale, are long flat slabs, with their surfaces longitudinally fluted, and uniformly ornamented with rows of deeply imprinted symmetrical figures; these are disposed with such perfect regularity, that the specimens are often supposed to be engraved stones, instead of natural productions. These fossils are the remains of the epidermis, rind or bark of the stems of gigantic trees; the regular imprints on the surface being the scars left by the separation of the leafstalks, as in the arborescent ferns just examined. The sigillaria are generally found lying in the horizontal position, and flattened by the superincumbent pressure; but a remarkable instance in which fern stems were found standing upright, with their roots in the soil, apparently in the position in which they grew, was brought to light near Manchester, England, during the excavations for a

What does the name Sigillaria mean? What is the appearance of a Sigillaria stem?