Chapter 8

[75]See Histoire des Végétaux Fossiles, pp. 29-34.

Vascular, or Acrogenous Cryptogamia.—These plants, as the name implies, possess a more complicated structure than the preceding, having vascular tissue as varied as in the phanerogamia.

Equisetaceæ.—The common species of Equisetum, or Marestail, is a plant that grows in marshy tracts, and on the banks of ditches and rivers; it has a jointed stalk, garnished with elegant sheaths which embrace the stem, and verticillate linear leaves: it attains a height of two feet, and is half an inch in diameter. In the fossil state there are many plants allied to the Equisetum, but only a few that are generically the same.

Lign. 12. Equisetum Lyellii.Wealden. Pounceford.nat.Fig.1.—A stem, having two sheaths, and a bud at the lowermost joint.2.—Stem of a young plant, with sheaths, preserved in pyrites.3.—Stem, with the cryptogamous head or upper end.

EQUISETITES.

Equisetum Lyellii,Lign. 12.—A species which I discovered in Wealden limestone, at Pounceford (Geol. S. E.p. 245), must have closely resembled theEquisetum fluviatile: it has an articulated cylindrical stem, and regularly dentated sheaths, embracing the stem at the joints.

A transverse slice of the stem exhibits under the microscope a cellular structure filled with calc-spar, and forms a beautiful object when viewed with the polarizing apparatus. This plant occurs in many localities of the Wealden in Sussex and Kent; from the railway cuttings near Tonbridge, I collected several fine specimens; it is met with also in the cliffs near Hastings.

Lign. 13. Equisetites columnaris.(Ad. Brongn. Pl. 13.)Lower Oolite. Whitby.Fig.1.—Portion of a stem, showing two articulations, and an intermediate constriction.1/3nat.2.—A few of the denticulations produced by the sheath,nat.

Equisetites columnaris.Lign. 13.—A gigantic species of Equisetum abounds in the strata of the lower division of the Oolitic or Jurassic formation of Yorkshire, and manyfine specimens have been collected, especially from the vicinity of Whitby. In the sandstone of the Inferior Oolite of the Cleveland Hills, Yorkshire, numerous stems of this colossal marestail have been observed standing erect, as if occupying the position in which they grew; the same fact was also discovered at Carlton Bank, near Stokesly, forty miles from the coast. In both localities fossil shells of fresh-water mussels (Uniones) were associated with the vegetable remains.

This plant is a true equisetum, differing chiefly from existing species in its gigantic size and arborescent character. The sheaths surrounding the stem, and the verticillate linear leaves, are preserved in some examples: and in all, the furrows left by the imprints of the sheaths are more or less strongly impressed. The stem is not channelled throughout, as inCalamites, the carboniferous plant whose stems at first sight might be mistaken for those of Equisetites, but which are entirely distinct, as will be explained hereafter. The Equisetites columnaris is peculiar to the Oolite; it does not occur in the coal-measures. Specimens have been discovered which indicate a height of twenty feet, and a diameter of several inches.[76]

[76]See Hist. Vég. Fossiles, p. 115.

A small species of Equisetum (Eq. Brodiei[77]) occurs in the insectiferous limestone of the lower Lias, at Strensham, Worcestershire, associated with the foliage of fresh-water endogenous plants resembling thePotamogeton, or pond-weed, and of supposed dicotyledonous vegetables.

[77]Prof. Buckman, in Geol. Journal, vol. vi. p. 413.

Lign. 14. Calamites decoratus.1/3nat.(Ad. Brongniart. Pl. 14.)Coal Formation. Yorkshire.Fig.1.—Part of a stem, showing the tubercles for the attachment of leaves.2.—A portion of the same on a larger scale.

CALAMITES.

Calamites.Lign.14,15.—Stem articulated, regularly furrowed longitudinally, the articulations naked, or studded with tubercles.

The plants of this genus were supposed to be related to the marestail, but to differ in the absence of the encircling sheaths, and in being uniformly striated; but an examination of specimens in a better state of preservation than those previously known, shows their affinity to the gymnosperms. Some of the species are of a gigantic size, being from one to three feet in diameter, and from thirty to forty feet in height. Calamites abound in the coal formation, and must have constituted an important feature in the forests of the carboniferous period; they occur also in more ancient deposits, and some species belong to the earliest terrestrial Flora of which any vestiges are known. In most instances when specimens are found lying in the same plane with the strata, they are pressed flat, but those occurring in a vertical position retain their natural cylindrical form. An outer crust or cylinder of coal generally invests the stem, but traces of the internal structure are rarely preserved.

The Calamite consists of a large central column of tissue, surrounded by a ligneous cylinder. The central part has in most instances perished after the death of the plant, and the cavity thus left been filled up with mineral matter. As the hollow ligneous zone is almost always carbonized, and very friable, it is seldom attachedto the cast, and consequently the surface of the latter is generally jointed and ribbed.

The true external surface of the cortical investment is marked with longitudinal striæ, without any indications of joints or constrictions; but the position of the original articulations is indicated in some specimens by thepresence of small verticillate scars, to which leaves were appended[78]as in the example figured by M. Brongniart, of whichLign. 14, fig. 1, is a reduced figure.

[78]See Mr. Dawes, "On the Structure of Calamites," Proc. Geol. Soc, 1851, vol. vii. p. 197.

Lign. 15. Calamites, in Coal Shale.Fig.1.—Calamites radiatus, with the remains of one of the sheaths.—1/2nat.2.—Stem, with remains of roots.—1/2nat.3.—Calamites approximatus, showing the curved lower end of the plant.[79]—1/5nat.

[79]This specimen has been inadvertently drawn with the base uppermost.

The stellate appearance on the upper part of the stem figured inLign. 15, fig. 1, is produced by the zone of leaveswhich surrounded the joint: this character is entirely distinct from the sheath of the Equisetum shown inLign. 12. This specimen points out the importance of carefully examining and preserving the stone around fossil stems; had this precaution been lost sight of in this instance, no knowledge would have been obtained of this important botanical character. It is rarely that any traces of the roots remain; the fossil figured (fig. 2) is from theFoss. Flor.A beautiful example of the foliage of a species of Calamites is represented inLign. 59, fig. 2.

Upright stems of Calamites occur in the Coal formation near Pictou, in North America; and in one example a group of ten or twelve stems, covering an area of two square feet, sprung from one root.[80]

[80]Dawson, Geol. Proc. vol. vii. p. 195. See Sir C. Lyell's Travels in North America, vol. ii. p. 195.

FOSSIL FERNS.

Filicites, or Ferns.

We now arrive at the consideration of one of the most interesting families of the vascular cryptogamia that adorned the Flora of the ancient world, and the living species of which impart beauty and elegance to the scenery of the countries where they prevail. The most essential character of these vegetables, is that of developing their fructification on the leaves; a fact familiar to every one who has even but cursorily examined the Polypody growing on our walls, or the Brake of our hedge-rows and commons. The largest species of British ferns scarcely exceed four or five feet in height; but the arborescent or tree-ferns, of warm climates, attain an altitude of from thirty to forty feet. There is too this peculiarity in the arborescent forms, that while in our indigenous species the leaves surround the stem, and incline towards the upper part of the plant, the foliage of the former bends downwards,and spreads out from the crown, or summit, into an elegant canopy.

Lign. 16. Pecopteris Sillimani;nat.Coal Shale. Ohio.a.The Stem.b.Leaf-stalk, or petiole.c.Leaf, or frond, which is bipinnate.d.e.Leaflets, or pinnæ; the upper,d, are entire;the lower,e, are pinnatifid.f.The pinnules, lobes, or segments.g.The midrib, or median vein.h.The veins. The veins are introduced in the leaflets,d;but in the lower ones,e, the midribs only are marked.

Lign. 16. Pecopteris Sillimani;nat.Coal Shale. Ohio.

The leaves of our branched ferns are persistent, and when shed, the markings left by their attachment to the stalk are soon obliterated. In the arborescent ferns, on the contrary, the petioles become detached from their bases, and fall entire, leaving scars or cicatrices on the stem; and these impressions are so regularly and symmetrically disposed, as to afford characters by which the trunks may be distinguished from those of other trees. The stems of the tree-ferns are therefore easily recognized in a fossil state externally, by their cylindrical forms without ramification, and by the regular disposition and peculiar character of thescars left by the separation of the petioles; and, internally by that peculiar zone, formed of bundles of ligneous tissue inclosed in sheaths, which encircles the central axis, as shown in the transverse sections inLign.2,ante,p. 62. The leaves may be identified by the form of their segments, which are disposed with remarkable regularity, and have a peculiar mode of subdivision; and above all, by the delicacy, evenness, and distribution of the veins. There are upwards of two thousand species of living ferns, and in the fossil kingdom the number is considerable; more than two hundred have been collected from the carboniferous formation. The recent tree-ferns are confined almost exclusively to the equinoctial regions; humidity and heat being the conditions most favourable to their development (Vég. Foss.p. 141.Bd.p. 461.Wond.p. 727).

From the elegance and diversity of form of their foliage, fossil ferns are the most remarkable and attractive vegetable remains in the ancient strata. The greater number are from the coal deposits, the fern-leaves generally occurring in the schists or shales that form the roof of the beds of coal. Many of the strata are made up of carbonized fern-leaves and stems closely pressed together. The roof of a coal-mine, when newly exposed, often presents a most interesting appearance, from the abundance and variety of leaves, branches, and stems, that occur either in relief, or impressed on the dark glossy surface. The specimens selected for illustration exhibit the principal modes of venation on which the genera are founded.

The fossil genera have been established by M. Ad. Brongniart, from the form of the leaves and the characters of their venation; that is, the distribution of the vessels. In the following descriptions some botanical phrases are necessarily employed; a few terms of frequent occurrence are explained inLign. 16.

Pachypteris[81](thick-fern).Lign. 17.—In this genus from the lower Oolite, the fronds are pinnated, or bipinnated, the leaflets entire, without visible veins, having but a single midrib, and contracted at the base. The absence of veins, and the leaflets not being lobed, are the essential generic distinctions.

[81]The names of the genera are derived frompteris, fern, to which prefixed a term indicative of the peculiar characters.

Lign. 17. Pachypteris lanceolata.Inferior Oolite. Whitby.

Lign. 18. Sphenopteris elegansCoal-shale, Waldenburg, Silesia.

FOSSIL FERNS. SPHENOPTERIS.

Sphenopteris(wedge-leaf).Lign. 18.—The leaves are twice or thrice pinnated, the leaflets wedge-shaped, contracted or narrowest at their base, and more or less deeply lobed: the lobes divergent and palmated: the veins radiating from the base.

The ferns of this genus are extremely elegant, and comprise upwards of forty species. A beautiful Sphenopteris (S. affinis,Wond.p. 716,) occurs abundantly in the fresh-water carboniferousstrata at Burdie House, near Edinburgh;[82]another elegant form, in coal-shale, is represented inLign. 18.

[82]See Dr. Hibbert's Memoir on the Strata and Fossils of Burdie House. 4to. 1835.

It is so rarely that the fructification of any species of Sphenopteris is preserved in a fossil state that I am induced to figure a leaflet of a remarkable plant, of this genus from the fluvio-marine oolitic deposits of Scarborough.Lign. 19is copied from the lithograph accompanying a notice of some rare plants from that locality, by the eminent botanist, C. J. F. Bunbury, Esq.[83]

[83]Geol. Journal, vol. vii. p. 179, pl. xii.

This fossil fern closely resembles certain species ofDicksonia(natives of New Granada). Each segment of the leaflet or pinnate is dilated at the apex into a reniformindusium; no capsules are visible, the fructification being, probably, in a young state.

Lign. 19. Sphenopteris nephrocarpa.Inferior Oolite, Scarborough.A magnified vein of a leaflet, showing the fructification at the extremities of the lobes, × two diameters.

Lign. 20.Sphenopteris Mantelli;nat.Wealden, Tilgate Forest.

In the Wealden deposits, both of England and Germany, several species of Sphenopteris abound; one of which (Foss. Tilg. For.1827), often occurs in the calciferous grit of Tilgate Forest, in a beautiful state of preservation: a small branch is figured inLign. 20. This species is characterizedby its slender and minutely divided wedge-shaped leaflets. The Sphenopteris Mantelli did not attain a considerable size; the largest stem I have seen indicated a plant of five or six feet in height. This Sphenopteris is sometimes associated with the remains of a beautiful plant of the genusAlethoptris,[84]the leaflets of which, in some examples, bear the fructification. (Wond.p. 394,Lign.89.)

[84]Alethoptris elegansof Dr. Dunker. Mon. Norddeutschen Weald, pl. vii.fig.7.

Lign. 21. Cyclopteris trichomanoides;a single leaflet;nat.Oolite, near Scarborough.

Cyclopteris(round-leaf).Lign. 21.—The frond is simple and entire, or but slightly lobed at the margin, and generally orbicular, or kidney-shaped: there is no midrib; the veins are numerous, equal, and dichotomous, or forked, and radiate from the base. The form and disposition of the veins resemble those of some living species of fern; the absence of a median rib, or vein, is the most strikingcharacter of this genus. The fructification is supposed to have been marginal.

FOSSIL FERNS. NEUROPTERIS.

Neuropteris(nerved-leaf).Lign.22.—The fronds are pinnate or bipinnate; the leaflets more or less ovate or cordiform and entire, adhering to the rachis by their centre only; veins very fine, arched, rising obliquely from the base of the leaflet; the midrib does not extend' to the apex of the leaflets, but terminates by subdividing into veins.

Lign. 22. Neuropteris acuminata;nat.In Coal-shale, Yorkshire.

This is a very numerous genus, comprising thirty or more species, which are principally found in the coal-shale. Some of these plants bear a general resemblance to theOsmunda regalis, but differ in their essential characters; their leaflets often form the nuclei of ironstone nodules.

Glossopteris(tongue-leaf).Lign. 23.—Leaves simple, sub-lanceolate, gradually contracting towards the base; midrib thick at the base, and vanishing towards the apex of the leaf; veins very fine, curved, oblique, frequently dichotomous,sometimes reticulated, or anastomosing at their base. The plants of this genus resemble the ferns with simple leaves. A few species only are known; of these, two are from the coal-shale, one from the Lias, and one from the oolite.

Lign. 23. Glossopteris Phillipsii;nat.Oolite, Scarborough.

Lign. 24. Odontopteris Schlotheimii;nat.Coal-shale of Saxony.

Odontopteris(tooth-leaf).Lign. 24.—Leaf bipinnate, the leaflets adhering to the rachis or stalk by their whole base, which is not contracted; the veins equal, simple, dichotomous, arising side by side from the base of the leaflet; no distinct midrib. In their general aspect these plants resemble some South American species of Osmunda. Five species only are known, all of which belong to the most ancient coal strata.

Anomopteris(anomalous fern—so named because the plants differ from all recent and fossil ferns).Lign. 25.—Leaves deeply pinnated; leaflets very long, entire, linear,traversed by a distinct midrib, equal throughout; secondary veins simple, perpendicular to the median vein, swollen at their free extremities, and not extending to the margin of the leaflet. But one species is known. These leaves are of great size, and doubtless belonged to some arborescent fern; in several examples the fructification is preserved. My collection contained a splendid specimen from near Strasburgh, presented by the late M. Voltz, which is now in the British Museum.[85]

[85]Petrifactions, p. 32.

Lign. 25. Anomopteris Mougeotii;nat.New Red Sandstone; Sultz-les-Bains, near Strasburgh.Fig.1.—Three leaflets of a very large frond.2.—A portion magnified to show the fructification.

FOSSIL FERNS. TŒNIOPTERIS.

Tœniopteris(wreathed fern).Lign.26.—Leaves simple, entire, straight, with parallel margins, traversed by a strong midrib, which extends to the apex; secondary veins, simpleor bifurcated at their base, and almost perpendicular to the median vein. These ferns are related to certain species of Polypodium. Three species are known; two from the Oolite, and one from a tertiary deposit. The specimen figured is a fragment.

Lign. 26. Tœniopteris latifolia;fragment of a frond; nat.Stonesfield Slate.

Lign. 27.Fig.1.—Pecopteris Murrayana; a pinnule with the fructification;magnified.Inf. Oolite, Scarborough.2.—Pecopteris lonchitica.Coal-shale, France.

Pecopteris(embroidered fern).Lign. 27.—Leaves once, twice, or thrice pinnated: leaflets adhering by their whole base to the rachis, rarely by the centre only; traversed bya strong midrib, which extends to the apex; veins simple, or once or twice dichotomous, proceeding almost at right angles from the median vein.

This genus embraces a very large proportion of the ferns which have contributed to the formation of the coal, and whose leaves and stems are preserved in the associated strata. The originals of many species were undoubtedly arborescent, and attained a large size; some leaves four feet wide, and of a proportionate length, have been observed. More than one hundred species are determined. An American species (Pecopteris Sillimani) is figured in illustration of certain botanical terms,Lign.16,ante,p. 110. Several species of Pecopteris occur in the fluvio-marine oolitic deposits near Scarborough, and leaves in fructification are not uncommon:fig. 1, Lign.27, represents a leaflet slightly magnified.

Lign. 28. Lonchopteris Mantelli.Wealden, Tilgate Forest.Fig.1. & 2.—Leaflets magnified, to show the reticulated venation.3.—A fragment of a frond;nat.

FOSSIL FERNS. LONCHOPTERIS.

Lonchopteris(spear-leafed.)Lign. 28.—Leaves many times pinnated; leaflets more or less adherent to each other at their base, traversed by a midrib; secondary veins reticulated.

The three known species which compose this genus resemblethe living ferns of the genera Lonchitis, Woodwardia, &c. Two have been found in the coal-measures, and one species in the Wealden formation of England and Germany (Foss. Tilg. For.pl. iii.) This last appears to have been a delicate plant; for though fragments are very common in the micaceous grits and clays, any considerable portion of a leaf is of rare occurrence. M. Graves found the same fern near Beauvais in France, in strata, which, from the presence of the fresh-water limestone called Sussex marble, are supposed to be referable to the Wealden epoch. This Lonchopteris is widely spread through the Wealden; and occurs also in the Greensand. Mr. Morris first observed it in the iron-sandstone of Shanklin Chine.[86]

[86]Geol. I. of W. 2dEd.p. 230.

Lign. 29.Fig.1.—Phlebopteris[87]Phillipsii.Oolite, Scorborough.2.—Phlebopteris propinqua,showing fructification.

[87]Comptopteris of M. Ad. Brongniart.

Phlebopteris(veined-leaf).Lign. 29.—Leaves pinnated; leaflets with the margin entire, or crenulated, themidrib strong; secondary veins anastomosing by arches, with large angular spaces, often unequally disposed; the finer veins are simple or divided; the apex sometimes free. The fructification is punctiform, and placed at the apices of the veins.

The foliage of these remarkable ferns has been mistaken for the leaves of dicotyledonous plants; but M. Brongniart has demonstrated that they belong to the present family. Six species have been found in the Oolite and Lias.

Lign. 30. Clathropteris meniscoides.Portion of a leaflet: the original 11/2ft. long.Wealden? Scania.

FOSSIL FERNS. CLATHROPTERIS.

Clathropteris(latticed-leaf).Lign.30.—Leaf deeply pinnatifid; leaflets elongated, traversed by a strong midrib extending to the apex; secondary veins numerous, simple, parallel, almost perpendicular to the midrib, united by transverse branches, which, with the finer veins, produce on the surface of the leaf a net-work of quadrangular meshes.

This genus was instituted by M. Brongniart, for the reception of some very large fern-leaves from the shale of Hoer, in Scania, which resemble in structure the foliage of the recentPolypodium quercifolium, a native of the EastIndies, and the Moluccas. One leaf was four feet wide, and the leaflets, though imperfect, were eighteen inches long.[88]

[88]Hoer is a little village, situated nearly in the centre of Scania, a province in the southern extremity of Sweden. The Chalk formation appears in several parts of this district, and Carboniferous strata at Hoeganes. To the west of Hoer, there is a range of hills, composed of ferruginous grits, micaceous sandstones, clays, and beds of quartzose conglomerate. It is in these strata that the ferns and other terrestrial plants occur, and no animal remains whatever have been found in them; their geological position appears to be between the Chalk and the Coal, but on this point nothing positive is known. The general analogy of the plants with the group forming the Flora of the Wealden, led M. Brongniart to suppose that the deposits in question belong to that formation; and M. Nillson, of Lund, who examined my collection at Brighton, recognized, among some undescribed plants from Tilgate Forest, forms that he had collected from Hoer. See "Observations sur les Végétaux Fossiles renfermés dans les Grès de Hoer en Scanie: par M. Ad. Brongniart."Ann. Sc. Nat.1825.

Many other genera of fossil ferns have been established from the form and venation of the leaves, and are described inBrit. Foss. Flor., and other British and foreign works.

Stems of arborescent Ferns.—Notwithstanding the profusion with which the foliage of many kinds of ferns is distributed throughout the coal formation, the undoubted stems of plants of this family are rarely met with; for the numerous tribe called Sigillariæ is now removed altogether from this class. It may, however, admit of question whether much of the foliage which, from the analogy of structure, has been referred to ferns, may not have belonged to those trees; for as in the animal kingdom, so in the vegetable, distinct types of living organisms are often found blended in the lost races; and as the stems of recent tree-ferns are even more durable than their leaves, it seems impossible to account for their absence in strata, that inclose entire layers of the foliage matted together. A few fossils, supposed to possess the essential characters of recent fern-stems, have been discovered, and arranged under the following genus.

FOSSIL FERN-STEMS.

Caulopteris(fern-stem).Lign.31.—Stems not channelled, marked with discoidal, oblong, or ovate scars, arranged longitudinally; vascular cicatrices numerous.

Lign. 31. Caulopteris macrodiscus.Coal.

The fragment of stem here figured, resembles the trunks of some recent tree-ferns in its proportions, and in the number, disposition, and size, of the scars of the leaf-stalks; but these markings differ in their more lanceolate form, and pointed terminations, and in their peculiarly striated surface, from those of any known existing species.

Psarolites(Silicified Fern-Stems).—In the New Red sandstone, near Hillersdorf, in the neighbourhood of Chemnitz, in Saxony, silicified stems, apparently of tree-ferns, occur in great numbers. They are remarkably beautiful, and the organization of the original is so well preserved by the silex, that slices, examined by the microscope, display the peculiar structure almost as perfectly as if the plants were recent: transverse sections exhibit the arched bundles of vascular fibres which compose the ligneous cylinder, surrounded by the cellular tissue. From the stellated markings produced by sections of the vessels that compose the tissues, and which are visible to the naked eye, these fossils have obtained the popular name ofStaaren-stein, or Star-stone. The external surface of the specimens I have examined has a ligneous structure, and is of a dark reddish brown colour; internally the stems are of a dull red, mottled with varioustints of blue and yellow, from the infiltrated chalcedony with which the vessels are permeated.[89]

[89]See Pict. Atlas (pl. viii.) for coloured figures; and Org. Rem. vol. L plate viii.figs.1-7. The reader will be amused by the perusal of the ingenious but unsuccessful attempt of the excellent author, Mr. Parkinson, to elucidate their nature. I have still a specimen which he presented to me more than thirty-five years since, as one of the most curious and perplexing fossils that had ever come under his notice.

An excellent work ("Dendrolithen") on these fossils, in which thirty species are described, has been published at Dresden by M. Cotta; who arranges them under the genusPsaroniusorPsarolites. The stem is composed of two distinct parts; an outer zone, consisting of a great number of nearly cylindrical bundles of vessels, supposed to have been roots which proceeded from the stem near its base; and an inner part or axis. In the outer portion, the fossilair-rootshave a vascular tissue, but there is often a delicate cellular tissue interposed. In the axis the vessels form zigzag or wavy bands, resembling those of ferns.[90]These flexuous and vermiform bands are entirely composed of barred or scalariform vessels, similar to those of ferns and club-mosses. The Psarolites are therefore considered by M. Ad. Brongniart to be the bases of the trunks of lycopodiaceous trees, while M. Cotta and other botanists regard them as true arborescent ferns.[91]

[90]Pict. Atlas, pl. viii.[91]See M. Brongniart's "Tableau des Genres de Végét. Foss." p. 44.

[90]Pict. Atlas, pl. viii.

[91]See M. Brongniart's "Tableau des Genres de Végét. Foss." p. 44.

Dr. Buckland has discovered in the New Bed sandstone formation at Allesley, near Coventry, silicified trunks of coniferous trees, and it is not improbable that further research in that locality may bring to light fern-stems like those of Chemnitz.[92]Dr. Lloyd, of Warwick, has recently obtained leaves of several coniferæ from the same locality.[93]

[92]Vide Geol. Proc. vol. ii. p. 438.[93]Geol. Society, June 1852. Dr. Lloyd's specimens are probably referable to the genusWalchia: seeLign.60.

[92]Vide Geol. Proc. vol. ii. p. 438.

[93]Geol. Society, June 1852. Dr. Lloyd's specimens are probably referable to the genusWalchia: seeLign.60.

Sigillarlæ and Stigmariæ.

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