detached; while yet a fourth species (Fig. 137), very closely resembles a Zamia of the Scarborough Oolite,-Z. lanceolata. The leaflets, however, contract much more suddenly

from their greatest breadth than those of lanceolata, into a pseudo-footstalk; and the contraction takes place not almost equally on both sides, as in that species, but almost exclusively on the upper side. And so, provisionally at least, this Helmsdale Zamia may be regarded as specifically

new.

northern outlier of the Lias, cones of a peculiar form, which, like the leaves themselves, are still unfigured and undescribed, and some of which could scarce have be

longed to any coniferous tree. In one of these (Fig. 138), the ligneous bracts or scales, narrow and long, and gradually tapering till they assume nearly the awl-shaped form, cluster out thick from the base and middle portions of the cone, and, like the involucral appendages of the hazel-nut, or the sepals of the yet unfolded rose-bud, sweep gracefully upwards to the top, where they present at their margins minute denticulations. In another species the bracts are broader, thinner, and more leaf-like: they rise, too, more from the base of the cone, and less from its middle portions; so that the whole must have resembled an enormous bud, with strong woody scales, some of which extended

from base to apex. The first described of these two species seems to have been more decidedly a cone than the other; but it is probable that they were both connecting

links between such leathern seed-bearing flowers as we find developed in Cycas revoluta, and such seed-bearing cones as we find exemplified in Zamia pungens. The bud-like cone, however, does not seem to have been that of a Cycadaceous plant, as it occupied evidently not a terminal position on the plant that bore it, like the cones of Zamia or the flowers of Cycas, but a lateral one, like the lateral flowers of some of the Cactus tribe. Another class of vegetable forms, of occasional occurrence in the Helmsdale beds, seems intermediate between the Cycadaces and the ferns at least, so near is the approach to the ordinary fern outline, while retaining the stiff ligneous character of Zamia, that it is scarce less difficult to determine to which

Fig. 140.

of the two orders of plants such organisms belonged, than to decide whether some of the slim graceful sprigs of foliage that occur in the rocks beside them belonged to the conifers or the club mosses And I am informed by Sir Charles Lyell, that (as some of the existing conifers bear a foliage scarce distinguishable from that of Lycopodiaceae), so a recently discovered Zamia is furnished with fronds that scarce differ from those of a fern. Even Zamia pectinata may, as Sternberg remarks, have been a fern. Lindley and Hutton place it merely provisionally among the

Cycadaceæ, in deference to the judgment of Adolphe Brogniart, and point out its resemblance to Polypodium pectinatum; and a small Helmsdale frond which I have placed beside it bears the impress of a character scarce less equivocal. The flora of the Oolite was peculiarly a flora of intermediate forms.

We recognize another characteristic of our Oolitic flora in its simple-leaved fronds, in some of the species not a little resembling those of the recent Scolopendrium, or Hart's-Tongue fern, a form regarded by Adolphe Brogniart as peculiarly characteristic of his third period of vegetation. These simple ferns are, in the Helmsdale deposits, of three distinct types. There is first a lanceolate leaf, from two and a half to three inches in length, of not unfrequent occurrence, which may have formed, however, only one of the four leaflets, united by their pseudofootstalks, which compose the frond of Glossopteris, -a distinctive Oolitic genus. There is next a simple ovate lan

ceolate leaf, from four to five and a half inches in length, which in form and venation, and all save its thrice greater

size, not a little resembles the leaflets of a Coal Measure neuropteris, N. acuminata. And, in the third place, there are the simple leaves that in general outline resemble, as I have said, the fronds of the recent Hart's-Tongue fern (Scolopendrium vulgare), except that their base is lanceolate, not cordate. Of these last there are two kinds in