cylindrical arms extended in every direction, branching oftentimes into two, and the smaller ones into two again, and thus occupying an area of many yards. From the little tubercles regularly arranged on the root there branched off innumerable rootlets, which we now find squeezed into narrow carbonised ribands, confusedly interlaced with the clay, and stretching for many feet away. These can only be seen fully developed when the form has been preserved by being embedded in a quartzose silt, like the ganister bed of some of the lower coals, when it becomes evident that each was attached by a curious rounded base resembling a ball and socket joint.

LEPIDODENDRON.

The trees of this beautifully marked family also attained a length of upwards of forty

Fig. 3. Lepidodendron obovatum. (Half natural size.)
(Le Botwood Colliery, Shropshire.)

feet, and are referred to some forty species. The size is the more extraordinary when we find that they are considered by botanists to belong to the Lycopodiacea

or club-mosses, the largest of which now living in tropical climates attains a height of only 3 feet.

An elegant cone, often found well preserved in ironstone among the coal shales, and termed Lepidostrobus, is now recognised as the fruit or catkin of the Lepidodendron.

Halonia, a stem from 2 to 4 inches thick, looking in outline like a knotty blackthorn, is reputed by Dawes and others to be the root of Lepidodendron.

CALAMITES. Jointed and striated stems occurring abundantly in some of the shales have been compared by the unlearned with bamboo, and by the earlier fossil botanists with Equiseta or "horse tails," of gigantic dimensions. But Brongniart in 1849 adduced reasons for doubting its being a cryptogamous or flowerless plant, and the later observations of Binney, Dawes, and Williamson associate it with Calamodendron as a concentric part of the same trunk, but leave its affinities in the modern world more uncertain than ever.

The Calamites have also been found in their original erect position, the root end terminating in a cone, for the most part curved.* They seem to have formed a dense brake of perhaps half the

height of the Sigillariæ.

* The conical end used to be taken for the top of the stem, and sometimes by collectors for a fish's snout.

ASTEROPHYLLITES. Under this name are grouped several kinds, perhaps genera of plants, characterised by the graceful arrangement of their leaflets in the form

W M.R QUICK

Fig. 5. Asterophyllites equisetiformis. Forest of Dean. (Natural size.) of a star. Some of the botanical authorities incline to consider it the foliage of the Calamodrendron, whilst others annex it to the Sphenophyllum, or wedge-leaf, and make the entire plant aquatic.

CONIFERÆ, or Firs. Among the trunks found petrified in the sandstones, many exhibit under the microscope a structure which proves them to belong to the araucarian division of pines, of which the species brought from Norfolk Island is a well-known modern representative. The coal-pines were peculiar from containing a very large pith, which, found separately as a ringed cylinder, used to be described as an independent plant, under the name Sternbergia. Angular, nut-looking fruits, called Trigonocarpum, are referred to this class of trees; and it is surmised that a roundish, veined leaf, which was formerly named

Cyclopteris, as being a fern, may have been the foliage of some of their species.

Again, in the films of soft mineral charcoal or "mother-of-coal," which, of the thickness of a knifeblade to a quarter of an inch (rarely), run evenly between the brighter laminæ of the coal, frequent in some, absent in other seams, the angular fragments of woody-looking substance, all mashed up together, present in many instances this araucarian structure. Other portions exhibit a bast tissue, or elongated cells, probably from wood of Sigillaria and Lepidodendron.

Of this confessedly highly-organised class of trees, the most abundant remains are referred to one genus called Dadoxylon.

FERNS OR FILICITES. These graceful relics of a former world of vegetation adorn the shaly roofs of many of the coal seams, sometimes clearly spread with their black tracery on a grey ground, a true specimen of nature-printing; at others tossed and tumbled in wild profusion throughout several feet in thickness of the roof-stone. A careful eye, and still better if aided by a microscope, may often see their traces in the coal itself, and in some of its dull unpromising parts may descry innumerable spiculæ or hair-like needles, which Dr. Dawson refers to the vascular bundles of decomposed plants of this tribe.

Certain of the botanists have named and described hundreds of species; others, more cautious, remind us that considerable difference of appearance may be seen on the several fronds of one plant, or even on the pinnæ of the same frond; and that the number of species may thence have to be reduced.

A general resemblance to ferns of the present day

Fig. 6. Pecopteris pteroides. (Half natural size.) (Forest of Dean.)
It is to be remembered that the whole

even genus.

of the coal-measure ferns

are utterly extinct, and their place in nature is supplied by fresh races. PECOPTERIS (adherent fern). The name ALETHOPTERIS is given to those species in which the pinnules are long and narrow. The leaflets adhere by their base to the rachis or stem, and are traversed by a strong mid-rib, from which veins branch off almost perpendicularly; some of them simple, some bifurcating, but never intersecting. Sometimes found with

Fig. 7. Pecopteris (Alethopteris) Searlii. (Half natural size.)

fruit patches (sori) in the back of the fronds.