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 Graminea, 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 Europea; Nymphoa odorata and Nymphaea alba; Ledum latifolium and Ledum palustre, Trientalis Americana and Trientalis Europea; 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.

Some

ing the analogy of distribution of the flora of both epochs. It shows the same degree of difference and of analogy. species, even a few types, peculiar to each country, the greatest number of them peculiar to America; many identical species, and especially many forms, so nearly related, that it becomes very difficult to separate them by specific characters.

Columbus, Ohio, April, 1860.

(To be continued.)

ART. X.-On an Oil-Coal found near Pictou, Nova Scotia; and the Comparative Composition of the Minerals often included in the term Coals; by HENRY HOW, Prof. Chemistry and Nat. Hist., King's College, Windsor, N. S.

THE name given to the substance I purpose describing indicates the use to which it is put, viz., the manufacture of paraffine-oil, and an inquiry into the association of elements in the minerals constituting the sources of this and similar "mineraloils" and in the bituminous coals, may possess some interest in a chemical point of view. As regards the classification of these it is not necessary to do more than recall the attempt made a few years ago in courts of law, in Scotland, New Brunswick and Nova Scotia, to decide what should and what should not be called a coal. The great array of evidence of various kinds brought to bear on the question rendered it a very interesting one, and it is well known that the opinions of the numerous scientific men consulted on these occasions were so nearly balanced that the point at issue was determined on the commercial, rather than on the scientific merits of the cases. It will be remembered that the substances in dispute were the Torbane-hill "coal," found near Bathgate in Linlithgowshire, Scotland, and the Albert "coal," occurring at Hillsborough, New Brunswick. As respects the former, the result of the trial in Edinburgh, in 1853, was that the jury considered it to be "coal, in the common sense of that word;" and, as regards the latter, it was decided at Fredericton, N. B., 1852, and at Halifax, N. S., to be also a "coal." Notwithstanding these legal decisions, which, from the conflicting opinions of witnesses, were obviously arrived at from other than scientific considerations, the question as to what is and what is not a coal, must be held to be an open one in those sciences in whose province the matter lies; and it will probably long remain so, because it was not from the absence of data, but from differing interpretations of facts about which for the most part there was a general accordance, that there arose the well known want of unanimity among geologists, mineralogists, chemists and microscopists.

In this paper I do not hope to decide the question, but I wish to point out as interesting facts the occurrence of true bituminous coal in contact with the Oil-Coal, and to call attention to the relative proportions of the ultimate elements in the latter and in the before-mentioned disputed substances as compared with bituminous coals, as important in explaining the different nature of their products of distillation, and in affording support to those who do not make one species only of these minerals.

Some of the analyses which follow are published for the first time; others, of my own, relating to bituminous coals, I have taken from among those given in the Report on Coals suited to the Steam Navy of Great Britain, by Sir H. Delabeche and Dr. Playfair, and those of cannel-coals are taken from sources hereafter indicated.

The oil-coal found near Pictou, N. S., was first met with by persons residing in the neighborhood, early in 1859, and its exact locality is called Fraser Mine. I occurs in the coal-measures. I am indebted to Henry Poole, Esq., manager of the Fraser Mine, for the following particulars relating to the geological position, etc., of the substance:

"The lowest measures about sixty yards, on the surface, short of the distance where the oil-coal crops, are composed chiefly of strong bands of sandstone, actual thickness not yet proved; then shales with bands of ironstone, and Stigmaria roots with Sigillaria stems, and a few detached fern leaves, in such soft shale that I have not been able to preserve any good specimens. Immediately above the oil-coal is a seam of bituminous coal about fourteen inches thick. Where we commenced to open a mine by driving a slope, the oil-coal was fourteen inches thick, but at 200 feet down at the bottom of the slope the oil-coal was twenty inches thick; it has a smooth regular parting at top next the coal, as also at the bottom next to the Oil-Batt below, but throughout its entire thickness it is of a curly twisted structure; many of its fractures look like the casts of shells, and the sharp edges are polished of a "slickensides" character. No fossils that I am aware of have hitherto been found in the curly Oil-Coal. The Oil-Batt next below is nearly two feet thick, of a homogeneous character with a slaty cleavage of various thicknesses. In this band two or three varieties (species?) of Lepidodendron beautifully preserved have been found, also leaves about onefourth of an inch wide, and in lengths of from four to six inches, which have undergone so little change, that when the damp shale was fresh split, they could be removed, and were so elastic that they could be bent considerably without breaking. At the bottom of the slope another thin seam of curly Oil-Coal has appeared of a few inches in thickness, but is not worked at present. In the roof-coal were found pieces of de

cayed wood very little changed, which I consider a great curiosity. On M'Lellan's Brook shale is above the Oil-Coal, and Oil-Batt below in which have been found Lepidodendra and apparently molar teeth with three fangs, flattened modiola shells, and spines or small fish-teeth. The Oil-Batt has been found in several places without the curly band or so-called Oil-Coal. Two thousand tons of Oil-Coal have been raised (Dec. 1859) at the Fraser Mine."

The Oil-Coal varies in color from brown to black, is dull where not polished as just mentioned, has a reddish-brown lustreless streak, its powder is dark chocolate colored, it is very tough and breaks at last with a hackly fracture, its specific gravity, in mass, after the vessel of water containing it had been in an exhausted receiver =1103. It takes fire very readily, and when removed from the lamp still burns for some time with a brilliant smoky flame, and flaming melted fragments continually drop from it in a truly characteristic manner. Ignited in coarse powder in an open crucible it gives off abundant smoke and flame, then seems to boil quickly, and a "coke" is left of the bulk of the original material, and showing when turned out a complete cast of the interior of the crucible. The ash of the "coke" is grey, and consists mainly of silicate of alumina, at least no lime or a mere trace is dissolved by acid, while some alumina is taken up and a great deal of solid remains undissolved. The powdered Oil-Coal digested with benzine and with ether does not more than sensibly color these finids, but some residue remains on evaporation in each case.

The bituminous coal occurring with the oil-coal had the usual characters belonging to its species; it was black, brilliant, and very brittle. The proximate analyses of the two are placed side by side and it will at once be obvious that they contrast very strikingly.

Volatile matters,
Fixed carbon,
Ash,

Bitum. coal.

Oil-coal.

66.56

33.58

The following is the ultimate analysis of the Oil Coal, for which I am indebted to Mr. Slessor, assistant to Prof. Anderson of Glasgow, whose aid I requested from want of the necessary apparatus: