merated by Dr. Newberry it would appear also that this genus is largely represented at some places and in restricted areas. Thus we may expect to see the number of American species largely increased.

The essential European types of this genus are all represented in our coal measures, either by identical species, or, by closely related forms. Thus we have: Sphenopteris spinosa Ll. and Hutt., S. tridactylites Brgt, S. Davalliaña Göpp., Sphenopteris irregularis Gutb., S. Gravenhorstii Brgt., S. Dubuissonis Brgt., S. latifolia Brgt., S. polyphylla Ll. and Hutt., S. artemisiafolia Sternb., &c. Besides, as American types, we have Sphenopteris flagellaris Lsqx., and especially Sp. Newberrei Lsqx. This last species has a ramification different from that of any other kind of fossil fern, viz., two secondary pinnæ, joined at their base and forking in an obtuse angle at the top of a short naked stem. The form of the leaflet and the nervation of this species is also peculiar. One of my species, Sphenopteris decipiens Lsqx. has, like Neuropteris adiantiles Lsqx., the primary nerve folded along the base of the leaflets and the nervules curved and branching upwards, a character ascribed by Brongniart to the genus Lonopteris Tom.

Hymenophyllites Göpp.-From analogy of nervation, rather than from a relation of typical form, I have, perhaps wrongly, connected with this genus, some species referable either to Aphlebia Sternb., or to Schizopteris Brgt., or even to Selaginites Brgt. Four American species: Hymenophyllites fimbriatus Lsqx., H. affinis Lsqx., H. hirsutus Lsqx., H. laceratus Lsqx., are represented by fronds which form a broad base, divide in ascending, and are thus irregularly cut in simple, ordinarily short, curved, somewhat obtuse lacinia or lobes. Each of the divisions is marked by a single nerve, ascending to its top. The fronds appear generally of a thick texture; but in H. giganteus Lsqx., which may be the same plant as Schizopteris lactuca Sternb., they are seemingly very thin. These species ought to constitute a separate genus. In the fossil flora of Pennsylvania I had attempted to group them together under the name of Pachyphyllum; but as some species have apparently thin leaves or fronds, the name could not be preserved of course. A discussion concerning the morphology of the plants of the coal would be out of place now. The subject ought to be separately treated. I needed only to mention these peculiar forms, for comparing the distribution of the genus Hymenophyllites. Two of our American species are closely related to the H. elegans Brgt. of Europe. The others, especially H. fimbriatus Lsqx., are apparently peculiar American types. This last, nevertheless, could be compared to Selaginites Erdmani Gutb.

Alethopteris Sternb.-All our American species have some affinity with European types of the same genus. Even the re

markable Alethopteris serrula Lsqx. is related, though distantly, to A. erosa Gutb., from which it differs, especially by its very long (sometimes 4 to 5 inches), narrow, linear pinnæ. It has been found only near Pottsville, Pennsylvania.

Callipteris Brgt.-One of the American species, C. Sullivantii Lsqx., is a beautiful fern of a peculiar character, apparently bior tri-pinnate, but of which pinnæ only have been found. The general outline of the pinnæ is like that of Alethopteris Serlii Brgt. But the pinnules are twice as broad, rounded at the top, marked by a broad and deep medial nerve, abruptly terminating in the middle of the leaflets, and from which emerge in acute angles, thin arched, forked nervules as closely placed as those of Neuropteris flexuosa Brgt. The other American species is closely related to Alethopteris sinuata Brgt. A. nervosa Brgt. is a common species over the whole extent of our coal fields. As it is generally found connected (though not on the same stem) with A. Sauveurei Göpp. (A. nervosa var. Brgt.), both forms are referable to the same species.

Pecopteris Brgt.-The identification of the species of this genus is difficult. Here, as with the Sphenopteridea, some species have been established on fructifications, which are seldom found in such a state of preservation that the form and the position of the fruit-dots can be ascertained, and others have been differently named from the branching of the veinlets, which differs in the same species according to the position of the leaflets. Thus identical species have received different names or even been placed in different genera. The number marked in the table represents only species of ours of which the value is ascer tained. Some of them show apparently true American types. Thus, Pecopteris Sillimani Brgt., P. Loschii Brgt., P. Velutina Lsqx., P. distans Lsqx., P. decurrens Lsqx., and Pecopteris concinna Lsqx., widely differ from any European fossil Pecopteridece known till now.

Caulopteris Brgt.-Uniting Stemmatopteris Corda, to this genus, we have at least four distinct species.

Stigmaria.-I think that the varieties of Stigmaria anabathra Corda, described by M. Göppert, are true species, being generally found in our coal-fields at different geological horizons. The five species described as new in the report of the Pennsylvania survey, may be perhaps reduced to three, but some well characterized species have been found since the report was made.

Sigillaria Brgt.-The distribution of this genus does not operate identically on the coal-fields of both continents. We have few species of the narrow-costate Sigillaria, more than 30 species of which are counted in Europe. We have more of the broadcostate forms and especially a large number of species belonging to the peculiar section of the smooth or rather uncostate Sigillaria.

In this last section, three well characterized forms are peculiar to our coal-fields. The one has its surface stellately wrinkled around the scars; the second is wrinkled crosswise, and the third has double, oval, obliquely-placed scars united by a deep groove, and the surface is beautifully reticulated by narrow wrinkles, obliquely intersecting each other. The beautiful Sigillaria Schimperi Lsqx., of which the large scars have nearly the form of an eye, is also a peculiar American form. The number of our species, as marked on the table, is too small. About ten new species belonging to the Geological State surveys of Kentucky, of Arkansas and of Illinois are not here counted.

Syrigodendron Brgt.-The two species described by Mr. Brongniart are common in America. I have never seen any other. Dr. Newberry indicates a peculiar species of ours under the name of S. Americanum Newb.

Lepidodendron Sternb.-The great number of specimens of this genus collected from the base and the top of the millstonegrit series of our coal measures, has afforded a good opportunity for examining the development and variations of the scars at the different stages of growth of the trees. Except L. oculatum Lsqx., which might be referred perhaps to L. distans Lsqx., all the new species described in the report of the survey of Pennsylvania are well characterized. Some of them might be considered as American types. L. distans Lsqx., is related, by the distance of the scars only, to Sagenaria rimosa Sternb.

Megaphytum Artis.-A beautiful and large specimen of a new species of this genus is preserved in the cabinet of the Geological State Survey of Illinois. Another new species is mentioned by Dr. Newberry under the name of M. discretum Newb.

Knorria Sternb.-The number of American species is apparently pretty large; but the difficulty of determining the species from specimens generally badly preserved has prevented or retarded the descriptions. Knorria imbricata Sternb., is especially common below the millstone grit.

Lepidophyllum Brgt.-We have already seven well characterized American species, and three new and unpublished ones. The number of peculiar forms of these scales or leaves of the cones of Lepidodendron, evidently shows that the large proportion of species of Lepidodendron, which have been found in America, cannot be considered as resulting from peculiar changes of the same species, according to the age of the scars. Lepidophyllum hastatum Lsqx., L. brevifolium Lsqx., and L. plicatum Lsqx., are American types not related to any European species.

Lepidostrobus Brgt.--The number of cones of Lepidodendron is extremely large, especially in the shales of the first bed of coal above the conglomerate. All the species ascertained, from the

form of their scales, apparently the only reliable specific character for a determination, are counted with Lepidophyllum.

The fruits distributed among the genera Cardiocarpum Brgt., Rhabdocarpos Göpp. and Berg., Trigonocarpum Brgt., Carpolithes Sternb., are generally found broken or flattened or divested of their outer envelope. Consequently the identification of the species is very difficult. The number of these fruits disseminated in the shales and in the sandstone of the low coal of our American basin is considerable. They follow the stratigraphical distribution of the genus Lepidodendron, though they do not appear in any way related to this genus. About twenty well marked but undescribed species ought to be added to those counted in the table. Some of them have peculiar forms without relation to any European species. One of the most remarkable, Rhabdocarpos arcuatus Lsqx., is described and figured for the fourth volume of the Geological Report of the State Survey of Kentucky, under the direction of Dr. D. Dale Owen.

Lycopodites Brgt.-Nothing, perhaps, shows more evidently the difference in the characters of the coal flora of both continents than the scarcity of species of Lycopodites and the abundance of species of Lepidodendron, in our coal measures; when a contrary distribution rather predominates in Europe. Both the genera are considered as closely related. Nevertheless we have a single species of Lycopodites, very rare indeed, since I found specimens of it only lately on both the extreme limits of the state of Kentucky, at the same geological horizon, viz., in the shale of coal No. 1B. By its concave leaves, decurrent and embracing at the base, it differs from any of the twelve European species of the coal yet described Dr. Newberry has not mentioned any species of this genus in his catalogue.

Asterophyllites Brgt.-As some species of this genus are represented by catkins, scarcely if ever found attached to the stems, and of which therefore the relation is obscure or unknown, I may have counted as peculiar to America a few species which are only fruiting modifications of some others. I consider those fruits as male catkins, attached to large branches, while the true fruit-bearing catkins, which are much smaller, were apparently terminating the branchlets;-a kind of fructification somewhat analogous, but in a position contrary to that of some pines.

Without including the species of Dr. Newberry, the table of distribution shows that from six hundred and fifty-five species of coal plants now determined; more than one hundred and sixty are peculiar to America; three hundred and fifty species are known only in Europe; and one hundred and fifty are common to both. It is certain that future researches will greatly add to the number of species common to both continents, but as much, also, to the number of species peculiar to America. There

fore, the difference pointed out by the table, may be admitted as fairly representing, in a proportional manner, the general distribution of the coal plants on both continents. The botanical remains of the coal-fields of Europe have been carefully collected and studied by learned naturalists for more than a century, while those of America are only beginning to be noticed by scientific explorers.

In the Introduction to the Fossil Flora of the coal-fields of Pennsylvania, I had already pointed out the great analogy existing between the plants now living on the peat-bogs of America and of Europe. Admitting the peat-formation of our time as being the actual representative of the coal-marshes of the coalepoch, I was led to the conclusion: that at this last epoch, the flora of both continents was as different and even more different than its representative flora is at our time. Thus, on twenty-five species of mosses growing on the peat-bogs and entering into the formation and composition of the peat, a single one is peculiar to North America. By extending my researches to the South, namely to the latitude of Norfolk, in the great Dismal Swamp of Virginia, I found the proportion changed in some manner; but nevertheless, the most common forms of the genus Sphagnum, which in Europe and North America form the principal mass of the peat, were found there also, performing the same work in the composition of the combustible matter. In the family of the Ferns, out of ten species growing on our marshes, five are identical with European species growing in the same situations; and two more are so closely allied to their European congeners that in a state of petrifaction, they could not be distinguished from each other. Even now, in their normal state, they are admitted by some botanists as varieties only. Among the Juncea, Cyperaceae and Gramineæ, twenty-six species out of forty-one are common to both continents; and from the other families, of which representatives are found on the peat-bogs, twenty-six species of thirty-one are found in Europe and in America. The likeness of some species of this section, peculiar to both continents, is still remarkable. Thus, Larix Americana and Larix Europaea; Nymphæa odorata and Nymphaea alba; Ledum latifolium and Ledum palustre, Trientalis Americana and Trientalis Europæea; Vaccinium macrocarpum and V. Oxycoccos (many others still could be named), are so nearly related that their specific characters can be distingnished only on good and complete specimens. There are, indeed, on the peat-bogs of America, some peculiar types which are not found in Europe: Xyris bulbosa, Taxodium distichium, Sarracenia purpurea, and a few others. But it is even so with the plants of the coal-period where we have seen certain types peculiar to this continent. This peculiarity serves only to render the more strik

SECOND SERIES, VOL. XXX, No. 88.-JULY, 1860.