Its

beds, and had an opportunity afforded me of examining the only ichthyic organism hitherto found associated with them; and was struck, though I could not identify its species, with its peculiarly Old Red aspect; but the evidence of the Cyclopterus is of course more conclusive than that of the fish; and we may, I think, legitimately conclude, that in Ireland, as in our own country, it was a contemporary of the great Pterichthys (P. major), - the hugest, and at least one of the last, of his race,—and gave its rich green to the hill sides of what is still the Emerald Island during the latter ages of the Old Red Sandstone, and ere the Carboniferous period had yet begun. The Cyclopterus Hibernicus, as shown both by the Prestonhaugh specimen and those of Ireland, was a bipinnate fern of very considerable size,-probably a tree fern. pinnæ, opposite in the lower part of the frond, are alternate in the upper; while its leaflets, which are of a sub-rhomboidal form, and so closely ranged as to impinge on each other, are at least generally alternate in their arrangement throughout. Among living plants it seems most nearly represented by a South American species,- Didymoclona pulcherrima,-one of the smaller tree ferns. The leaves of this graceful species are bipinnate, like those of the fossil; and the pinnæ (thickly set with simple, alternately arranged leaflets) are opposite in the lower part of the frond, and alternate in the upper. Widely as they are separated in time, the recent South American Didymoclona and the Old Red Sandstone Cyclopterus, that passed into extinction ere the times of the Coal, might be ranged together, so far at least as appears from their forms, as kindred species. It were very desirable that we had a good monograph of the Irish Old Red plants, the contemporaries of the latter, as the completest and best preserved representatives of the Middle Paleozoic flora yet found. Sir Roderick Murchison

has figured a single pinnæ of this Cyclopterus in his recently published "Siluria;" and Sir Charles Lyell, both that and one of its contemporary Lepidodendra, in the last edition. of his "Elements." These interesting fragments, however, serve but to excite our curiosity for more. When urging Professor Edward Forbes on the subject, ere parting from him for, alas! what proved to be the last time, he intimated an intention of soon taking it up; but I fear his purposed monograph represents only one of many works, important to science, which his untimely death has arrested for mayhap long years to come.

In the uppermost beds of the Upper Old Red formation in Scotland, which are usually of a pale or light yellow color, the vegetable remains again become strongly carbonaceous, but their state of preservation continues bad,— too bad to admit of the determination of either species or genera; and not until we rise a very little beyond the system do we find the remains of a flora either rich or well preserved. But very remarkable is the change which at this stage at once occurs. We pass at a single stride from great poverty to great wealth. The suddenness of the change seems suited to remind one of that experienced by the voyager, when, after traversing for many days some wide expanse of ocean, unvaried save by its banks of floating sea weed, or, where occasionally and at wide. intervals, he picks up some leaf-bearing bough, or marks some fragment of drift weed go floating past, he enters at length the sheltered lagoon of some coral island, and sees all around the deep green of a tropical vegetation descending in tangled luxuriance to the water's edge,tall, erect ferns, and creeping lycopodiacea, and the pandanus, with its ærial roots and its screw-like clusters of narrow leaves, and, high over all, tall palms, with their huge pinnate fronds, and their curiously aggregated

groups of massive fruit. And yet the more meagre vegetation of the earlier time is not without its special interest. The land plants of the Old Red Sandstone seem to compose, all over the world, the most ancient of the terrestrial floras. It was held only a few years ago, that the Silurians of the United States had their plants allied to the Lepidodendron. But the group in which these occur has since been transferred from the Upper Silurian to the Old Red System; and we find it expressly stated by Professor H. D. Rogers, in his valuable contribution to the "Physical Atlas" (second edition, 1856), that "the Cadent [or Lower Old Red] strata are the oldest American formations in which remains of a true terrestrial vegetation have yet been discovered." It has been shown, too, by Sir Roderick Murchison, that the supposed Silurian plants of Oporto are in reality Carboniferous, and owe their apparent position to a reverse folding of the strata. I have already referred to the solitary spore-cases of the Ludlow Rocks; and beneath these rocks, says Sir Roderick (1854), "no remains of plants have been discovered which are recognizably of terrestrial origin." Scanty, too, as the terrestrial flora of the Old Red Sandstone everywhere is, we find it exhibiting very definitely the leading Palæozoic features. Its prevailing plants are the ferns and their apparent allies. It has in our own country, as has been just shown, its ferns, its lepidodendra, its striated plants allied to the calamites, and its decided araucanite; in America, in the Cadent series, it had its "plants allied to ferns and lepidodendra; " and in the Devonian basin of Sabero in Spain, its characteristic organisms are, a lepidodendron (L. Chemungensis), and a very peculiar fern (Sphenopteris laxus).* But while

"Though the coal of Sabero is apparently included in Devonian rocks," says Sir Roderick Murchison, "M. Casiano de Prado thinks that this appearance may be due to inverted folds of the strata." On the other

in its main features it resembled the succeeding flora of the Carboniferous period, it seems in all its forms to have been specifically distinct. It was the independent flora of an earlier creation than that to which we owe the coal. For the meagreness of the paper in which I have attempted to describe it as it occurs in Scotland, I have but one apology to offer. My lecture contains but little; but then, such is the scantiness of the materials on which I had to work, that it could not have contained much: if, according to the dramatist, the "amount be beggarly," it is because the "boxes are empty." Partly, apparently, from the circumstance that the organisms of this flora were ill suited for preservation in the rocks, and partly because, judging from what appears, the most ancient lands of the globe were widely scattered and of narrow extent, this oldest of the floras is everywhere the most meagre.

hand, M. Alcide D'Orbigny regards it as decidedly Old Red; and certainly its Sphenopteris and Lepidodendron bear much more the aspect of Devonian than of Carboniferous plants.

LECTURE TWELFTH.

ON THE LESS KNOWN FOSSIL FLORAS OF SCOTLAND.

PART II.

IN the noble flora of the Coal Measures much still remains to be done in Scotland. Our Lower Carboniferous rocks are of immense development; the Limestones of Burdiehouse, with their numerous terrestrial plants, occur many hundred feet beneath our Mountain Limestones ; and our list of vegetable species peculiar to these lower deposits is still very incomplete. Even in those higher Carboniferous rocks with which the many coal workings of the country have rendered us comparatively familiar, there appears to be still a good deal of the new and the unknown to repay the labor of future exploration. It was only last year that Mr. Gourlay* of this city (Glasgow) added to our fossil flora a new Volkmannia from the coal field of Carluke; and I detected very recently in a neighboring locality (the Airdrie coal field), though in but an indifferent state of keeping, what seems to be a new and very peculiar fern. It presents at first sight more the appearance of a

* Now, alas! no more. In Mr. Gourlay the energy and shrewd business habits of the accomplished merchant were added to an enlightened zeal for general science, and no inconsiderable knowledge in both the geologic and botanic provinces. The marked success, in several respects, of the brilliant meeting of the British Association which held in Glasgow in September, 1855, was owing in no small measure to the indefatigable exertions and well calculated arrangements of Mr. Gourlay.