references to localities beyond the Devonshire border have been simply intended to show the consecutive character of my argument, and the general applicability of the rules laid down. Here therefore I stop, leaving it to others who possess the all-essential local knowledge to carry the enquiry further if they will.

There remains but one other point for comment. The only other record of ancient British topography which we possess beyond those already commented upon or alluded to, is the list of thirty-three cities which is commonly ascribed to Nennius. I cannot find in that list any name which by any process of accomodation can be associated with Devon or indeed with Cornwall, save possibly Cair Teim; for Cair Pensauelcoin, as Mr. Kerslake has shown, is certainly not Exeter.

To place my suggestions as clearly before my readers as possible, I have appended a map to this paper, on which they are set forth.

No reference has been made to the work of other commentators, either in agreement or disagreement, because it has been felt that the hypotheses advanced must stand or fall upon their own merits, and that whatever weight rightly attaches to the opinions of the many distinguished men who have enquired into these matters, their views are but opinions, and cannot in any case be cited as conclusive authority. The only "authorities" indeed are the original authors under review, and the vestiges of antiquity by whose aid the riddle has been attempted to be solved. If the system here set forth for the interpretation of the Ravennat is the right one, it will prove itself in the very fact that it is capable of systematic application; and as a system by the results of that application it must stand or fall.

THE MOSS Flora of Devonshire, for some reasons unexplained, has attracted many admirers and a few excellent workers, whose names will be found attached to the various species and varieties enumerated in the following list. The Rev. Mr. Tozer, whose name so frequently occurs in the cryptogamic portion of the Flora of Devon, appears to have been the leader in this particular department, and his knowledge of the various forms elicited a very high eulogium from one of the best of British cryptogamic botanists, Dr. Greville. Mr. Tozer's collection of the genus Hypnum-as the genus was known to him before it got divided into the various sections and genera as it now is-is in the Devon and Exeter Institution.

Dr. Greville, while on a visit to this favoured county in search of health, turned his attention to collecting the Mosses of Devon. The result was, that two fasciculi of the species collected, as well as some northern species, are now in the above institution. This collection was made in 1819-20. In 1823 Dr. Greville began to publish the Scottish Cryptogamic Flora, illustrated with some of the most accurate and beautiful figures that have ever been executed in the United Kingdom. From the visit of Dr. Greville to this county, up to the publishing of the Flora Devoniensis in 1829, I am not aware that anything was done in this department of Botany in Devon. From that time a long break seems to have occurred. I began myself to collect the Cryptogams when I first came into the county in 1848, and have been adding to them slowly ever since. A part of the result of my labours have been published in our Transactions; viz. the Lichen Flora, and I have now the pleasure of offering you another

instalment in the Moss Flora of Devon. Messrs. E. M. Holmes and F. Brent have however preceded me in publishing a list of the Mosses and Hepatice of Devon and Cornwall. The names of these gentlemen will be found attached to those found by them, so that each one is responsible for those species. The name of Mr. E. D. Marquand will also be found attached to many species. This gentleman, who made a moss-collecting tour in 1884, very kindly communicated to me the localities of his rarest finds. Mosses, although plants of humble growth, more especially in this country, play a very important part in the economy of Nature. They were in all probability the pioneers of the vegetable kingdom; but of this we have no absolute evidence, as no fossil Musci, so far as I am aware, has ever been found. Their structure, generally speaking, is not adapted to resist decay so well as that of vascular plants. Mosses and lichens, by attacking the otherwise almost impervious rocks and stones, insinuate their fibrous roots into the crevices, keep up an almost continuous moisture, which, in course of time, and with the assistance of the frost in winter, help to reduce the apparent adamant to decay; so much so, that we might apply to them the appellation of the "teeth of time."

Mosses of various kinds, but more especially those of the genus Sphagnum, which form a most important item in the growth of our peat bogs, play a much more important part than is generally ascribed to them in the retention of the water which falls on our high lands and on mountains. Were it not for these mosses, the water retained by them would soon be dissipated into space by the action of the sun's heat and the absorbing atmosphere, and many of our towns and villages would be sorely pressed for want of this necessary of life.

But these bog mosses take possession of the hollows on the rocky hill or mountain side, and the water as it falls from the clouds being retained by them, instead of running away directly, or being evaporated, gradually gets away by slowly percolating through, and so we get a number of rills, which become at length, by augmentation of other rivulets, and by further additions, rivers. Thus the water supply is kept up, and it is but a step from this to the water supply of our towns. See how many are dependent on the supply obtained from Dartmoor! And more might be supplied. But strip the rocky base of its moss covering, and the consequence would be a very intermittent supply,

and the greater part of our moorlands would become arid wastes.

The following extract is from an important work on the Fenlands of Norfolk, Cambridge, and Lincolnshire. The authors say that:

Peat.-"The bog moss Sphagnum, which constitutes the bulk of the peat of Ireland, and much of that of England and Scotland, is in the fens a rare plant. Its place is taken by a strong-growing form of Hypnum fluitans. Peat is entirely confined to the temperate zones of the earth, and is most plentiful in the cooler portions thereof. At the present time the climate of Britain is too mild to allow of its vigorous growth, and even in Scotland it is wasting away quicker than it grows. The authors consider that at least 7000 years have elapsed since the climate was favourable for the growth. of peat. Five distinct forests have been traced in the peatbogs of the fens, marking, as they think, five distinct dry epochs, when that which was bog became dry ground, and remained so sufficiently long for the trees to take possession and grow into a comparative forest. Then came on a wet period, when these were swamped, died, and fell, and at length covered with moss.

A large tract of the peat land on Dartmoor was taken a few years ago by a company for the manufacture of compressed peat. They erected works on the spot, with machinery and ovens for drying; laid down a railway from the works to the Bridestowe Station on the South Western Railway; and spent a great many thousands of pounds. They discovered, after all this was done, that with their best peat they could not compete with coals; and the lighter portion, for fire-lighting, they found could not be produced at a price that gave them any remuneration. One of the great difficulties they had to contend with was the wet season. They could not dry the peat by natural means, and built large ovens, or kilns; but this took away all profits, and had to be abandoned.

The next scheme projected was the utilizing the fibrous portion of the peat only, for stable purposes-the beddingdown of horses, &c.--so that the peat would absorb all the produce of the stable, and make it a valuable manure. They put up machinery for the purpose of tearing the peat in pieces, and sifting out the dry earthy particles. The fibre was then packed into bales, and ready for use. It was soon found, however, that to produce this cost too much; and, besides this, they could not compete with the northern 'Fenland," p. 555. 2 A

VOL. XVII.

companies. The northern peat is better for this purpose, being more fibrous. Now it is projected by another company, who have lately bought off the whole concern, to utilize the black or densest portion of the peat, and convert it into charcoal. To carbonize this will require kilns or ovens to be built there; but there is still that old difficulty staring them in the face-the drying in bad or wet seasons. It is conjectured by the most sanguine that this carbonized peat will be found of great utility in purifying the sewage of large towns. By this means the peat would become a very valuable manure.

On a careful examination of the area and cuttings for these peat works, I found that the peat varied in thickness from three or four to six and seven feet; the thickest is about seven feet, when the cutting comes to the granite. The vegetation on these peat-fields is of a very meagre description. At the present time very little of the true bog mosses, the Sphagni, are to be found there; but the vegetation is chiefly composed of the following plants: Polytrichum commune, &c., Eriophorum vaginatum, Carex recurva, Juncus squarrosus, Calluna vulgaris, Sphagnum obtusifolium, S. acutifolium, and two or three species of Dicranum. There was a time, however, when apparently the sphagnums predominated; for I found a thick band composed of little else at about four feet from the surface. Below this the peat is very much decomposed, and cuts out like soap. Being very dense, it requires a great deal of drying before it can be put to any use, and it is this portion that the company now think to carbonize for sewage purposes.

Above the layer of sphagnums rests a band of strong fibrous matter, composed of tough roots, with thick tufts of the roots of rushes and carices scattered through it. Similar tufts are seen in all the upper portion of the peat to the surface, where some, no doubt, of the same species are now growing; but no trees, or plants of larger growth than the Calluna vulgaris and the whortleberry (Vaccinium myrtillus); and on enquiry of the person in charge of the works, I could not hear that any larger plants had been found in the cuttings.

From the sphagnum band the whole of the upper peat is of a light and very porous nature, and when dry is scarcely of any use except for fire-lighting. It quickly consumes away, and will not bear any comparison with coals.

It is probable, I think, that before the mosses had attained to the highly-developed structures-comparatively speaking