102 THE GEOLOGIST. sizes, agreeing in nothing so much as the particularly slender and narrow shape of the leaflets and branches. They look like parsley leaves, coriander leaves, mimosa, and some again look like what they are — finely divided ferns. Figure 7* shows the peculiarly graceful character of the tribe. There are several other kinds of " opteris", with which, as the Scotch song says, "I'm laith to vex ye." But I must mention one that is not very common in the coal, but which has been found in a perfect state in some beds older than the coal, both in Ireland and in Scotland. This is the Adiantites Hibernicus, a fern first brought to notice by that eminent man and ardent naturalist, Edward Forbes. It is common in some rich fossil beds in the upper part of the Old Red Sandstone of Ireland. It puts one in mind of the fern which is the glory of Killarney—the King or Royal-fern, Osmunda regalis—about the same size, and with the spreading broad leaflets set on a broad stem. But whereas our Killarney friend carries her fruit on her head, that is to say, the terminal leaves and pinnee are changed into fruit-bearing spikes, the fern that grew in old old times on the margin of thePateozoic bogs has its lower or bottom pinnae crowded with seeds.

(To be continued.)

ON THE DISTRIBUTION OF CEPHALASPIS AND PTERASPIS IN .

BY GEOEGE E. ROBERTS.

I HOPE our scientific tourists of the approaching season will take their good eyes into Herefordshire quarries. For now that the Scotch mono­ poly of the Old Red fishes is broken up, they will be found to repay time and trouble, if searched for in that and the adjoining counties; and something like a reasonable history of these strange old littoral fishes may be the result of a single season's work. There is a great deal about them well worth, knowing, and their remains will be found tolerably abundant, though very fragmentary, both in the sandstones and corn stones ; and therefore I have a peculiar pleasure in intro­ ducing our primaeval fish-fauna to the notice of those on search already—or hoping to be as the season advances—for relics of ancient life. Before I call particular attention to some fruitful localities, let me say a few words upon the physical condition and geographical aspect of the age they lived in. Though I ought rather to say ages, for they anticipated the advent of the system they are popularly said to belong to—that vast life-era—the extent of whose inland-seas and shallow littoral ocean-zone we see in the sandy, shaly, and gravelly beds which contain our fishes, and of whose deep seas the thick-bedded

* The figures of Sphenopteris ScMotheimii, Adiantites Hibernicus, and Osmunda regalis will be given in the next number. ROBERTS—DISTRIBUTION OF CEPHALASPIS AND PTEEASP1S. 103

limestones of Devon are witnesses—called by us Old Red or Devonian; and first appeared upon the stage in true Upper Silurian times ; for the Pteraspis Ludensis of the Lower shales of Leintwardine (county Salop), is the oldest representative of the family. Its discovery in these older rocks, though of great interest, did not in the least surprise me; for a sea-deposit, so clearly marked out as littoral by its starfishes and its shrimp-like Crustacea, would be the natural home of shore-fishes, which Cephalaspides undoubtedly were. Moreover, the shells and fuci which the Lower Ludlow rock has everywhere in keeping, tell a certain tale of its shallow-water condi­ tion ; and enable us by studying them to read with greater ease and increased interest, the record written by succeeding seas. Indeed, if we are to understand the physical aspect of the Old Red age, we must make ourselves well acquainted with the foregoing Silurian; for no aid will be of greater value to us, or more beautiful as a study, than the slow and gradual transition from the deep-sea condition which prevailed over the border-counties I am calling attention to, during the accumulation of the marine limestone of the Wenlock series, and the inland lakes of brackish water, terminated, probably, by wholly freshwater conditions, which have left us the fine silty shales of the Upper Old Red as their legacies. And thus it comes to pass, that not only for the first stages of its new physical career, but also for the birth-place of its life-forms, the Upper Silurian age is insolubly linked with the Old Red Sand­ stone ; and in every exposure of these older rocks, which contain littoral crabs and star-fishes, we may reasonably expect to find the ancestry of the ancient shore-fishes I am describing. But though they thus anticipate the age they are popularly said to belong to, they did not—so far as we know—live beyond the close of the Old Red system; and beyond doubt their metropolis is in the grey and red cornstones of Herefordshire and Worcestershire. The position of these beds (see section, page 104), which are seen in many places in these border counties to pass through a tilestone series into the underlying Silurian, is now clearly made out, and only their fossil history waits our reading. And this must be learnt by us before the true contemporaneous relations of the two very distinct rock-series which we together know as the Devonian system can be cleared up ; before we can see what com­ munication, if any, existed between the shallow waters which laid sandy sediment in Herefordshire, and the deeper ocean, which has left us hard coral-rock and shells, in Devon. Upon the physical boun- . daries of these waters, Eichwald has some instructive remarks in a short memoir prefacing the fish-fauna of his " Lethcea Rossica," in which he points out the marked difference between fishes of the shore and fishes of the open sea, and describes some new forms of osseous fishes from the Devonian rocks of Russia, not unlike our English Cephalaspids. And now I will mention the results of my own hunting among the Old Red quarries, and I hope, by thus putting others upon the trail, many good fishes may be taken. For more specimens are wanted before even their (precise) position 104 THE GEOLOGIST.

Great Conglomerate.

/,/M ' Upper Sandstones.

Upper Cornstones. m

Cepkalaspis asterolepis and C. \ Lyellii, Pteraspig Lloydii (?), j Grits and Sandstones, ^ O

c^vj // Lower Cornstones.

Cepkalaspis Lyellii, Pteraspis') Grits. Lloydiiy and P. Lewisii. ) Upper Tilestones.

Lower Tilestones.

CephaZaspis Lyellii (?) and C.~\ ///•/ Mtvrchisoni, Pteraspis rostra- > A ///A Downton Sandstones. tits and P. Bamksii. ) I ^w' f Upper Ludlow Rocks. Pteraspis truneatus, P. Banksii,^ and P. rbstratus, Cepkalaspis > 1 Aymestry Limestone. Salweyii, C. Lyellii (?), Auch- > • enaspie Saltert. J Pteraspis Ludentia.

Lower Ludlow Rocks, g,

Pteraspis Ludensie. ROBERTS—DISTRIBUTION OF OEPHALASPIS AND PTERASPIS. 105

among fish-families can be decided. Probably a kinship existed between the two chief forms of ichthyic test of Oephalaspis and Pteraspis, and it is most likely that our noble friend, the sturgeon (Acipenser), will have to own them of his family; for, as Prof. Hux­ ley has lately pointed out, they bear, in shape and arrangement of head-plates, a great affinity to the genus Spatularia, a North American attache of our larger and caviare-giving fish. It may help the comprehension of those who are unfamiliar with the osseous head-shields of these old ganoid fishes, if I sketch the two forms whose acquaintance will be most easily made by exploring collectors, Oephalaspis and Pteraspis. Form of shell is a very deceptive guide both in fish and crustacean life ; indeed, if we made our affinities from this alone, one great genus would include many species of both orders, for the shape of Cephalaspidean bucklers is copied almost literally by several Crustacea. A new Harpes from the Silurian limestones of Oesel, figured by Eichwald, agrees not only in shape of head, but even a position of the eyes with Oephalaspis; while it would be a matter of serious concern where to draw the line between the head-plates of Eurypteris and Oephalaspis. But it is from the closest and most minute examination that species and even families are determined among those which lived during the infancy of vertebi ated life.

A, Oephalaspis Head-shield. B, Pteraspis Head-shield (as usually found"). 1, Ornamented external layer. 1, External ridged layer. 2, Intermediate cancellated layer. 3, Internal shell layer. * A restoration of this is promised us by Prof. Huxley.

Pteraspis Ludensis, the oldest fish with which we are at present acquainted, was found in the Lower Ludlow mudstones at Churchill Quarry, near Leintwardine, and has been well described and figured, side by side with its ally, Pteraspis truncatm, from the Upper Ludlow rocks, by Mr. Salter, in the "Annals of Nat. Hist." for July, 1859. VOL. IV. O 106 THE GEOLOGIST.

P. Ludensis ranges up into the Upper Ludlow shales, in which it was found as far back as 1852 by Dr. Harley, of King's College. I have not heard of other Cephalaspids being found in Upper Ludlow rock, but in the Downton sandstone they reappear, and are abundant in the neutral ground lying between that rock and the tilestones, and still keep the company of Euryptera and Pterygoti. The Down- ton sandstone is well displayed near Kington; where in a quarry near Bradnor Hill, two forms of Pteraspis were discovered by Mr. Richard Banks. These are described and figured by him in the Greol. Soc. Journ., vol. xii., p. 93. The noted railway-section near the Ludlow station is in the zone of these passage-shales, and has been most indefatigably worked by Messrs. Lightbody and Marston. Other exposures of these fish- bearing shales occur, though all are not equally prolific. The earliest true Cephalaspis comes to us from the lowest layer of the passage- bed. Auchenaspis, an allied genus was first found in the Ludlow ex­ posure of the shales, but lately our best specimens have come from a south-east extension of the bed, cut through by the railway near Ledbury. An interesting memoir of this exposure will be found in the Geol. Soc. Journ., vol. xvi., pp. 193-7. Its author, the Rev. W. S. Symonds, proves the existing relationship between the Ludlow and Ledbury deposits; and notes the discovery of Pteraspis in red and mottled marls and sandstones (passage-rocks), lying above Downton sandstones at the tunnel-mouth; and of abundance of Auchenaspis (which may be described as a small Cephalaspis with a neck-collar, or plate filling up the space behind the eyes, and between the cornuted prolongations of the shield), in. the top layers of the transition beds, answering in stratigraphical position to those on the Ludlow railway. The upper tilestones are the next repositories of Cephalaspids with which I am acquainted. Many good specimens of Pteraspides came out of this rock when it was quarried at Trimpley, near Kidderminster, and two heads of Cep>halaspis Murchisoni (?) were met with by me ; but when I saw the locality last, some very fine potato-plants were making good use of their time just over the hole which had given me good fossils, and two cottages near-hand owned the quarry as a garden; so no more Pteraspides at Trimpley. But one notable exposure is left to us at Whitbatch, three miles north-east of Ludlow—a classical spot as having given the late Dr. Lloyd the first Pteraspis buckler, which still retains its name of P. Lloydii. The relationship between these tilestones and the overlying hard cornstone rock, pare enough in this neighbourhood to be burnt for lime, is plainly to be seen in the quarries in the- Downton drive, and a more instructive walk cannot be taken than that leading through the Whitbatch woods to Hayton, Sutton, and . Indeed, it is to this ground that I wish to direct the special attention of travelling geologists, for I cannot think it has had full justice done to its merits. Pteraspis is not uncommon in fragments among the tilestones in the great quarry on the west side of the drive to the Hall—by the way, there is a band of corn- ROBERTS—DISTRIBUTION OP CEPHALASPIS AND PTERASPIS. 107

stone interstratified, which must not be confounded with the true Old Red cornstone which is quarried and tunnelled into beyond this quarry—and I have lately met with some bits of fish-armour, with cunningly convoluted striee, fragments of a related though, as yet, undescribed genus. These also occur in a brown-red coarse grit, at the Wall Hills, near Ledbury, though higher in stratigraphical position. I have said that through the Whitbatch portal we enter a very fine field of research, but our route must be advisedly taken ; and I do not recommend another halt in our march until we have left Down- ton Hall and its woods behind us, and are looking down from the high grounds of Hayton, upon the beautiful dale of the Corve. If we trace northward from Upper Hayton the lines of cornstone in out­ crop parallel to the course of the Dale, we shall come to some notable exposures. At some points, Hayton's Bent, for example, they are cupriferous, though the poorness of the ore obtained, (a carbonate), has yielded but little copper, and failure has attended the works. And at another spot, near the farm-buildings of Downton Hall, they have yielded an ore of lead, in the well-known form of cubic galena. But it is for fishes we are searching, not metals. There is a small quarry in a field at the top of Hayton, which one would think a terrible place from its being called the " Devil's mouth," but there is nothing alarming about its appearance, nor has it any strange connections that I could see, save its treasures of Cephalaspid fish. I think I never saw Pteraspis Lloydii of equal size to those I have taken in this quarry, though I could meet with no other species. The stone is here a fine-grained light-coloured sand-rock, inter­ stratified with true cornstone. Two miles east of this place, in the Upper Cornstones of Hopton Cangeford, the monarch of the Cepha- laspides in point of size, the great G. asterolepis, was found by Dr. Harley. More of this noble fellow when we mount up to him in time, and ascending order of beds. On the same horizon, and yielding more or less evidence of their former life are the cornstones of Hall's Barn, near Kidderminster, and of Cradley, near Malvern. In both places I have found frag­ ments of Cephalaspis and Pteraspis in abundance ; but I need hardly remind the collecting geologist that good scutes are of very unfrequent occurrence; themajority of specimenshavingbeenlaid with the breccia­ like gravel, whose weight and unequal pressure were enough, even if motionless and undisturbed by currents, to have broken up the shell­ like plates. And in fact such an amount of grinding did actually take place among the shallows and pebble-reaches of the Old Red lagoons, that more than one layer of coarse grit lying above the lower cornstone is seen by a lens to be crowded with blue and purple atoms of fish-shell, the triturated remains of many a good Pteraspis. Steering north, with a slight easterly inclination, from the Hayton quarry, we shall find several breakages into the lower cornstones, near the apex of the ridge, at Sutton and Bouldon and . Pteraspidean plates are to be found at each of these places, and a halt 108 THE GEOLOGIST. may be advantageously made at every quarry. The Sutton quarry is well worth staying at,forhere the head-plates of Pteraspis are of frequent occurrence, and are much better preserved than elsewhere, phosphate of iron having coloured them blue and purple, and chemically fixed the outer striated layer of shell—so seldom found in position—to the internal cancellated and filmy ones. At Bouldon too, in the quarry near the mill, Pteraspis is not unfrequent; but the cornstone is coarser, made up of larger and more angular pebbles, and the fossils have suffered many breakages from being laid in their company. On the opposite side of the dale, good Pteraspides have, I believe, been found at Norton, a small village nearly opposite to Hayton; and if we turn eastward from that point, and skirt the foot of the Titterstone Hill, we shall get some specimens of much interest from a quarry near Farlow. Indeed, the finest specimen of P. rostratus I ever saw, came from a sandstone rock occurring with cornstones, near the forge in that village. There is another good exposure of fish-bearing Old Red which has had scant justice done to it—the beautiful country lying north of Brom­ yard. At Hinston and Acton Beauchamp, near this town, Cephalaspis Salweyi has been met with. This is a large species, having its enamel layer covered with "pearly drop-like tubercles" of small size, which, together with its other distinct characteristics of shape and ornamen­ tation are described by Mr. Harley, in the Quart. Journ. Geol. Soc, vol. xv., p. 504. I think it likely that the Upper Cornstones occur near Tedstone Delamere, though I have been unable to verify this by a visit. This hard brecciated band is well worth searching for, as it contains in the two openings made into it, of which I am aware, that very beau­ tiful species, Cephalaspis asterolepis—the monarch, by virtue of size and ornamentation, of the " Buckler-heads." A short memoir is given by Mr. Harley, in the Quart. Journ. Geol. Soc, vol. xv., p. 503, which, as we learn from a note appended, will be incorporated with the description of Cephalaspides to be published by the Geological Survey. The outer surface of the head-shield possessed by this regal fish is ornamented by tubercles, variable in size, but larger than those of G. Salweyi. But the most wonderful structure is that of the inner plate—borrowing the words of Mr. Harley—" It presents lacuna? and long branching canaliculi precisely resembling those of human bone. Many of these are completely injected with a transparent blood-red material; and so beautifully are they thus displayed, that one ignorant of the structure of bone would be able to apprehend it by a glance at a minute part of this ancient fragment. So wonderfully indeed has nature treasured up her secrets in this disentombed relic of a time so distant as to be incalculable, that she distinctly reveals in their minutest details the structure of canals not more than the one fifty- thousandth of an inch in diameter, and such as defy the skill of the anatomist to inject." Several good specimens of G. asterolepis have been from time to time obtained by me from an exposure of the Upper Cornstones at Heightington, near Bewdley. But the mine js now NOTES AND QUERIES. 109 exhausted; for my good friend, Mr. Baugh, of Bewdley, who has followed up my researches in Worcestershire by constant and unwearied attention, assures me that no other specimens can be got from the stone brought up from the now filled-up quarry. Less is known about the tuberculated Cephalaspides than of those whose head-shield is ornamented by scale-like area, marked out by the out-cropping of minute vascular canals, entering the disk from beneath, and exhausting them­ selves upon its surface. This true reading of the external appearance of G. Injellii is contained in a paper by Prof. Huxley, in the Quart. Journ. Geol. Soc., vol. xiv., p. 270. Equally careful and minute is the description there given of the layers which unite to form the cephalic shield of Pteraspis. Briefly their characters may be thus given—the innermost layer is a thin delicate lamina of enamel, some­ what nacreous, and occasionally tinged with colour; the middle layer is composed of vertical plates of like substance, so arranged as to enclose polygonal cells, whose summits or external apertures are closed by an excessively delicate filmy layer, minutely reticulated; and lastly the outer plate consists of a hard layer, strongly ridged, whose summits are turned outwards. In one species I have observed the external edges of these ridges to be minutely toothed. Most of the characters of this triple armour are shown in the annexed sketch of Pteraspis. Thus I have briefly called attention to the occurrence of these fishes in several places, though their condition is usually fragmentary, in the Old Red of England. And so, we bid our adieus to these shield-bearing ancients ; but only that we may meet them elsewhere, and obtain from them in the field their willing tribute to our scientific treasury. Much has been written about them, but more remains to be said. And while the story yet to be told is in the careful keeping of an accurate naturalist, any collector who can find and contribute a readable frag­ ment may be proud of being associated, not only with a memoir of the earliest known fish, but also with that which dignifies the study of Cephalaspis and Pteraspis—the history of the first appearance of vertebrated life.

NOTES AND QUERIES.

TERTIARY STRATA IN KENT.—DEAR SIR,—It has been aptly said by one of your correspondents that deep railway-cuttings, though presenting difficulties to the engineer, are great helps to the geologist; and the sections exposed in the new , Chatham, and Dover Railway, are particularly interesting in showing the geological features of East Kent. As one who lias taken deep interest in the geology of the county, and has studied these cuttings, particularly that over the chalk near Canterbury, at Beakeshourn, perhaps I may be permitted to give a short account of them, through the medium of your valuable journal.