Lesquereux.] now. [Jan. 5, lites have there, also, some rare representatives. In the Pseudo-carboniferous, characterized as it is now by the species published by Prof. Andrews, from the Waverly Sandstone of Ohio, and those determinable from the specimens from Port Byron, Ill., the Paleopteris continues to be present. But some of the species have lobed or decomposed leaflets, tending by these characters to a section of the Sphenopteris, which comes later. The predominant forms are those of Megalopteris, a splendid fern whose advent is not prefigured in the flora of the Catskill by any species known until But in its large leaflets and its nervation, it evidently betokens the great family of the Neuropteridea to which belong the most beautiful and varied forms of the coal plants. The same rock group has rare species of Alethopteris, also with very large fronds and leaflets, Hymenophyllites, and broadly winged fruits of the genus Cardiocarpon. One species of Paleopteris, similar to P. obtusa, is remarked in this division as well as in the Catskill group. And on another side it has some species of Lepidodendron, Lepidophloios, a small Asterophyllites, etc., which continue higher up, and enter the sub-carboniferous measures. We have as yet too little data in regard to the flora of the Catskill, and that of the Pseudo-carboniferous to be able to positively recognize the points of affinities and of difference. Most of the species have been described from Canada and Maine, and their age generally ascribed to the Devonian, or marked under the indefinite appellation of pre-carboniferous. The flora of the sub-carboniferous division is, per contra, known by a large number of its species. It is allied to the pseudo-carboniferous by those which are named above; by species of Sphenopteris, Triphyllopteris, Eremopteris, and espe cially of Alethopteris, of analogous types. It has for its own predominant characters some Neuropteris, with large fronds and small leaflets as N. Smithii, which though extremely abundant in Alabama and Virginia, has not as yet been discovered in the coal measures above the Millstone grit ; Neuropteris tenuifolia, which persists even to the highest strata of the coal, is there also. Professor Fontaine has seen in the Vespertine of Virginia species of Odontopteris, a genus predicted by the fine Eremopteris marginata of the pseudo-carboniferous. This one partakes of the Odontop teris type, quite as much as of the Eremopteris character, recalling also something of the facies of Megalopteris, which has not been seen in the subcarboniferous until now. In this last division, the number of species is, as stated, greatly multiplied, and it becomes now difficult to positively mark those which are limited to it. The Lepidodendron, especially, are extremely abundant. The old types L. Sternbergii, L. Veltheimianum, L. aculeatum. etc., appear mixed with more recent ones, and with others which seem peculiar to this division: as L. squamiferum from the Helena vein of Alabama, which bears upon its bark true scales, easily detached, and at the same time, the scars of leaves generally remarked upon the trunks and branches of Lepidodendron. The collateral genera are represented also: U7odendron, Halonia, Lepidophloios, Knorria; Stigmaria is there in abundance, though remains of Sijillaria are as yet extremely rare. Among the species which have been considered in Europe as characteristic of the Mountain Limestone of the culm, we have in the sub-carboniferous of Alabama and Virginia Alethopteris nervosa, A. muricata, and Sphenopteris Hæninghausii, this as common in the shale of the Helena coal as Neuropteris Smithii. These three species, however, ascend in the American coal measures to above the Millstone grit, which, though a kind of geological delimitation, as well traced here as in Europe, is not a very definite line of demarcation between the vegetable groups. For, with few exceptions, the lower carboniferous flora has still the types of the sub-carboniferous, merely modified, and represented by an increased or diminished number of species. The ly copodiaceous are still more abundant; and we have, especially in the lower veins, immediately above the Millstone grit, the largest number of species of Lepidodendron and Ulodendron. Stigmaria and Sigillaria have gained in predominance; and in the ferns, new species of Neuropterida, especially some large-leaved Neuropteris and Odontopteris, are seen for the first time. The wide-ranged Alethopteris Serlii, and its analogous species A. lonchitica, are there also; the first already seen in the sub-carboniferous, the second a derivation of A. Helena, of the same lower division. A. Pennsylvanica and A. Sullivantii, may be counted too in the first coal above the conglomerate, as prefiguring in their more important characters those of the Callipteris, which comes later in order of time. For one specics of this last genus only is known in the lower carboniferous, and another from the Cannelton coal, already somewhat high up in the measures. As the largest number of the species of plants of the coal have been obtained from the lower carboniferous, it would be possible to continue the enumeration of the species which are considered as proper to it or as characteristic. But subsequent researches may greatly reduce the number; for as yet few strata bearing remains of plants have been discovered in the upper carboniferous. This division may be limited from the base or from the top of the barren measures underlying the Pittsburgh coal; for indeed we know as yet nothing of the flora of these barren strata. In ascending from the Millstone grit, after passing the two first coal beds above it, the vegetation is rapidly modified in its characters by the gradual disappearance of the Lycopodiaceous types, and the increasing predominance of the ferns. The species of Sigillaria continue in about the same proportion; Annularia, Sphenophyllum, Asterophyllites, become more abundant. And while some of the generic di visions of the ferns, like Alethopteris and the large-leaved Pecopteris, seem to pass away; the group of the Cyathea, represented by Pecopteris arborescens, P. oreopteridia, P. polymorpha, etc., become the more numerous, and especially characterize the upper carboniferous. They mostly belong to tree ferns, which, besides the extreme abundance of their pinnæ in the highest veins of Pennsylvania, have left, petrified in the sandstone of Ohio and Virginia a prodigious quantity of trunks representing whole forests. With these there is no trace of Lepidodendron; some Sigillaria are left. The vegetable world was at that period a world of ferns, mixed with the Cordaites, a race of as yet undetermined relation, it seems, half-ly copodia Lesquereux.] [Jan. 5, ceous, half conifers. These plants are mostly known by their long linear, ribbon-like leaves; their stems have been very rarely found. Some large, bushy species of Neuropteris have persisted. N. hirsuta and N. Loschii ascend from the Millstone grit to the Permian. And above the Pittsburgh coal or even in connection with it are found the Callipteris: Callipteris Moorii, and Callipteris conferta, this last species one considered in Europe as Permian, and found by the Virginian geologists, Fontaine and White, in the highest strata of the carboniferous. We have seen, however, that many other so-called Permian types are remarked in the American coal measures already from below the millstone grit; and therefore, it is not as yet advis able to consider as Permian those upper strata which, beside this Callipteris, have a number of representations of truly carboniferous species. It remains only to state how far the work on the American coal flora has progressed towards its completion. The plates, sixty in number, are all ready. The number might be still further increased by several species which cannot be clearly represented by descriptions only; but wood cuts may be used for the purpose, if it is advisable and possible to have any intercallated into the text. The description of the species and the remarks upon their diversified characters, as seen in the comparison of the specimens, have been all written, and, therefore, the manuscript may be definitely prepared in a short time. It is, however, not yet in its final shape, as the records have to be left open for the admission of any valuable data which the continued communications of materials may bring to the Flora. This synopsis is very incomplete, but it cannot be made comprehensible without the tables of distribution, even if a large number of species were enumerated. Moreover the limitation of the vegetable groups is not yet definite enough. New and indeed very desirable discoveries, especially of plants of the Lower Carboniferous, the Vespertine of Pennsylvania, and the Devonian Hamilton Coal Measures of the Juniata, may compel important modifications. Therefore, the divisions as marked above, as well as their names, should be considered only temporary. They are subject, of course, to geological evidence which ought to govern them. The final nomenclature of the groups of the " Coal Flora must accord with that of the Second Geological Survey of Pennsylvania. Tabular Synopsis of the Rhynchophora of America. (See Minutes of January 5, 1877.) Dr. Le Conte presented a tabular statement of the number of species of Rhynchophora, contained in the XV. volume of the Proceedings of the Society, and their geographical distribution in the different zoological provinces of temperate North America. He mentioned the instances in which the occurrence of similar extraordinary forms in geographical regions very remote from each other corresponded with what he had previously shown in the other higher types of Coleoptera, and again expressed the opinion that the isolated and feebly represented, though sometimes widely distributed forms in insects were representative survivals of the faunæ of former geologic periods; and proceeded : It is useless to oppose this view by the statement that these composite, synthetic, prophetic or undifferentiated types have not yet been found in the strata, for every well-informed entomologist will remember that except in Tertiary strata but few localities have presented specimens sufficiently preserved to permit accurate study. Moreover the localities thus far explored are all in the temperate zone, where we may reasonably not expect to find the predecessors of the larger and more conspicuous forms. In the older rocks the insect remains are so compressed, and the sutures of the most important elements of the external skeleton so obliterated, that but little knowledge can be had except from the venation of the broad winged orders. In this respect there is, as I can state from information furnished me by Dr. Hagen, a striking correspondence between some of the Carboniferous lace-winged insects and our own existent Pteronarcys. But in fact. Pteronarcys, being peculiar, among all genera of similar form and appearance, by possessing in the adult distinct remnants of the larval branchise on the anterior segments of the abdomen, would necessarily, by my method of interpreting structures, be regarded as a survival of an ancient form, even if no Miamia wing had been found in the coal quarries. A better appreciation of the characters of resemblance, which ally the more important groups represented at present in the various classes of animals, as contrasted with the differences between them and their analogues of former periods, the remains of which are found in the rocks, and which are occasionally represented by survivals of insignificant size or restricted area, will enable entomologis ́s to take broader views of the capabilities of the branch of science which they cultivate; but in which too often their attention is directed to squabbles about nomenclature, orthographic or historical, and to the simple enlargement of our knowledge by the description of generic and specific forms. |