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APPENDIX.

1.-COMPARATIVE VIEW OF THE SUCCESSIVE PALÆO

ZOIC FLORAS OF NORTHEASTERN AMERICA AND
GREAT BRITAIN.

In eastern Canada there is a very complete series of fossil plants, extending from the Silurian to the Permian, and intermediate in its species between the floras of interior America and of Europe. I may use this succession, mainly worked out by myself,* to summarise the various Palæozoic floras and sub-floras, in order to give a condensed view of this portion of the history of the vegetable kingdom, and to direct attention to the important fact, too often overlooked, that there is a definite succession of fossil plants as well as of animals, and that this is important as a means of determining geological horizons. A British list for comparison has been kindly prepared for me by Mr. R. Kidston, F. G. S. For lists referring to the western and southern portions of America, I may refer to the reports of Lesquereux and Fontaine and White.t

In this connection I am reminded, by an excellent little paper of M. Zeiller, † on Carboniferous plants from the region of the Zambesi, in Africa, that the flora which in the Carboniferous period extended over the temperate portions of the northern hemisphere and far into the arctic, also passed across the equator and prevailed in the southern hemisphere. Of eleven species brought from the Zambesi by M. Lapierre and examined by M. Zeiller, all were identical with Euro

*“Acadian Geology,” “Reports on Fossil Plants of Canada,” Geological Survey of Canada. f “Geological Surveys of Pennsylvania, Ohio, and Ilinois.”

Paris, 1883.

T

pean species of the upper coal-formation, and the same fact has been observed in the coal flora of the Cape Colony.* These facts bear testimony to the remarkable uniformity of climate and vegetation in the coal period, and I perfectly agree with Zeiller that they show, when taken in connection with other parallelisms in fossils, an actual contemporaneousness of the coal flora over the whole world.

1. CARBONIFEROUS FLORA.

(1) Permo-Carboniferous Sub-Flora :

This occurs in the upper member of the Carboniferous system of Nova Scotia and Prince Edward Island, originally named by the writer the Newer Coal-formation, and more recently the PermoCarboniferous, and the upper beds of which may not improbably be contemporaneous with the Lower Permian or Lower Dyas of Europe. In this formation there is a predominance of red sandstones and shales, and it contains no productive beds of coal. Its fossil plants are for the most part of species found in the Middle or Productive Coal-formation, but are less numerous, and there are a few new forms akin to those of the European Permian. The most characteristic species of the upper portion of the formation, which has the most decidedly Permian aspect, are the following:

Dadoxylon materiarium, Dawson. * Walchia (Araucarites) robusta, Dn. * W. (A.) gracilis, Dn. * W. imbricatula, Dn.

Calamites Suckovii, Brongt.

C. Cistii, Brongt. * C. gigas, Brongt.

Neuropteris rarinervis, Bunbury,
Alethopteris nervosa, Brongt.
Pecopteris arborescens, Brongt.
* P. rigida, Dn.

P. oreopteroides, Brongt. * Cordaites simplex, Dn.

Of these species, those marked with an asterisk have not yet been found in the middle or lower members of the Carboniferous system. They will be found described, and several of them figured, in my Report on the Geology of Prince Edward Island.”+ The others are

*

Grey, “Journal of the Geological Society," vol. xxvii. 7 1871.

common and widely diffused Carboniferous species, some of which have extended to the Permian period in Europe as well. From the upper beds, characterised by these and a few other species, there is a gradual passage downward into the productive coal-measures, and a gradually increasing number of true coal-formation species.

It is worthy of remark here that the association in the PermoCarboniferous of numerous trunks of Dadoxylon with the branches of Walchia and with fruits of the character of Trigonocarpa, seems to show that these were parts of one and the same plant.

This formation represents the Upper Barren Measures of West Virginia, which are well described by Fontaine and White,* and the reasons which these authors adduce for considering the latter equiralent to the European Permian will apply to the more northern and eastern deposits as well, though these have afforded fewer species of plants, and are apparently less fully developed.

(2) Coal-formation Sub-Flora :

The Middle or Productive Coal-formation, containing all the beds of coal which are mined in Nova Scotia and Cape Breton, is the headquarters of the Carboniferous flora. From this formation I have catalogued + one hundred and thirty-five species of plants; but, as several of these are founded on imperfect specimens, the number of actual species may be estimated at one hundred and twenty. Of these more than one half are species common to Europe and America. No less than nineteen species are Sigillariæ, and about the same number are Lepidodendra. About fifty are ferns and thirteen are Calamites, Asterophyllites, and Sphenophylla. The great abundance and number of species of Sigillariæ, Lepidodendra, and ferns are characteristic of this sub-flora; and among the ferns certain species of Neuropteris, Pecopteris, Alethopteris, and Sphenopteris greatly preponderate.

These beds are the equivalents of the Middle Coal-measures, or Productive Coal-measures of Pennsylvania, Ohio, &c., and of the coal-formation proper of various European countries. Very many of the species are common to Nova Scotia and Pennsylvania; but in proceeding westward the number of identical species seems to diminish.

*“Report on the Permian Flora of Western Virginia and South Pennsylvania,” 1880.

† " “Acadian Geology,” and “Report on Flora of Lower Carboniferous," 1873.

(3) The Millstone Grit Sub-Flora :

In this formation the abundance of plants and the number of species are greatly diminished.* Trunks of coniferous trees of the species Dadoxylon Acadianum, having wide wood-cells with three or more series of discs and complex medullary rays, become characteristic. Calamites undulatum is abundant and seems to replace C. Suckovii, though C. cannæformis and C. cistii continue. Sigillario become very rare, and the species of Lepidodendron are few, and mostly those with large leaf-bases. Lepidophloios still continues, and Cordaites abounds in some beds. The ferns are greatly reduced, though a few characteristic coal-formation species occur, and the genus Cardiopteris appears. Beds of coal are rare in this formation; but where they occur there is in connection with them a remarkable anticipation of the rich coal-formation flora, which would thus seem to have existed locally in the Millstone Grit period, but to have found itself limited by generally unfavorable conditions. In America, as in Europe, it is in the north that this earlier development of the coal-flora occurs, while in the south there is a lingering of old forms in the newer beds. In Newfoundland and Cape Breton, for instance, as well as in Scotland, productive coal-beds and a greater variety of species of plants occur in this formation.

The following would appear to be the equivalents of this formation, in flora and geological position :

1. The Seral Conglomerate of Rogers in Pennsylvania, &c.

2. The Lower Coal-formation Conglomerate and Chester groups of Illinois (Worthen).

3. The Lower Carboniferous Sandstone of Kentucky, Alabama, and Virginia.

4. The Millstone Grit and Yoredale rocks of northern England, and the Culmiferous of Devonshire.

5. The Moor rock and Lower Coal-measures of Scotland.

6. Flagstones and Lower Shales of the south of Ireland, and Millstone Grit of the north of Ireland.

7. The Jüngste Grauwacke of the Hartz, Saxony, and Silesia.

(4) The Carboniferous Limestone Series :

This affords few fossil plants in eastern America, and in so far as known they are similar to those of the next group. In Scotland it is richer in plants, but, according to Mr. Kidston, these are largely

*“Report on Fossil Plants of the Lower Carboniferous and Millstone Grit of Canada,” 1873.

similar to those of the underlying beds, though with some species which extend upward into the Millstone Grit. In Scotland the alga named Spirophyton and Archæocalamites radiatus—which in America are Erian—appear in this formation.

(5) The Lower Carboniferous Sub-Flora :

This group of plants is best seen in the shales of the Horton series, under the Lower Carboniferous marine limestones. It is small and peculiar. The most characteristic species are the following:

Dadoxylon (Palæoxylon) antiquius, Dn.-A species with large medullary rays of three or more series of cells.

Lepidodendron corrugatum, Dn.-A species closely allied to L. Veltheimianum of Europe, and which is its American representative. This is perhaps the most characteristic plant of the formation. It is very abundant, and presents very protean appearances, in its old stems, branches, twigs, and Knorria forms. It had well-characterised stigmaria roots, and constitutes the oldest erect forest known in Nova Scotia.

'Lepidodendron tetragonum, Sternberg.
L. obovatum, Sternb.
L. aculeatum, Sternb.
L. dichotomum, Sternb.

The four species last mentioned are comparatively rare, and the specimens are usually too imperfect to render their identification certain, but Lepidodendra are especially characteristic trees of this horizon.

Cyclopteris (Aneimites) Acadica, Dn.-A very characteristic fern, allied in the form of its fronds to C. tenuifolia of Goeppert, to C. nana of Eichwald, and to Adiantites antiquus of Stur. Its fructification, however, is nearer to that of Aneimia than to that of Adiantum.

Ferns of the genera Cardiopteris and Hymenophyllites also occur, though rarely.

Ptilophyton plumula, Dn.- This is the latest appearance of this Erian genus, which also occurs in the Lower Carboniferous of Europe and of the United States.

Cordaites borassifolia, Brongt.

On the whole, this small flora is markedly distinct from that of the Millstone Grit and true coal-formation, from which it is separated by the great length of time required for the deposition of the marine limestones and their associated beds, in which no land-plants

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