There are four obvious sources of information regarding former conditions of the land. First comes the testimony of historical documents, then that of place-names, next that of tradition, and lastly, that of geological evidence.
(1) One might suppose that for what has taken place during the historical period, the documentary records would be all sufficient. But as it is only recently that the subject has been determined to be worthy of the historian's serious attention, we cannot look for much light to be thrown upon it in the pages of the ordinary histories. Still less need we expect to meet with any full measure of information regarding it in the original documents from which such histories have been mostly compiled. In truth, the facts of which we are in search must be gleaned from brief allusions and implications rather than from actual descriptions. It was no part of the duty of an old chronicler purposely to record any natural fact, short of some terrific earthquake or storm that destroyed human life and damaged human property. But in describing historical events he could hardly avoid reference to woods, lakes, marshes, and other natural features which served as boundaries to the theatre of these events. By comparing, therefore, his local topography with the present aspect of the same localities, we may glean some interesting particulars as to changes of landscape in the course of centuries. Such a comparison, however, to be effective and trustworthy, involves two special qualifications. The inquirer must be master of the language and style of the author he is studying, and he must be completely familiar with the present condition of the ground to which allusion is made. The want of this combination of knowledge has led to some curious blunders on the part of able scholars.
It is evident, then, that an ample domain of research is here opened out to the student. In a general sense, every kind of historical document may be available for the purposes of the inquiry. England fortunately possesses in Domesday Book the results of a minute examination of the greater part of the country in the latter half of the eleventh century. For other portions of our islands much information may be gleaned in quarters that might be thought the most unlikely. Besides the narratives of the old Chronicles, which might be expected to contain at least occasional incidental reference to physical features, Charters and other legal documents, in dealing with the holding and transference of land, not infrequently throw light on the former aspect of the ground with which they are connected. The Cartularies of some of our ancient abbeys, besides affording glimpses into the inner life of these establishments, which do not seem to have been always abodes of peace and studious retirement, give indications of the former areas of forest, woods and mosses, or the positions of lakes now reduced in size or effaced. Old Acts of Parliament, looked at from our present point of view, are by no means always repulsive reading. They have one great advantage over their modern representatives in that they are often commendably brief; and in their occasional quaint local colouring, they afford material for interesting comparison with existing topography.
Among historical documents I include poems of all kinds and ages. Our earliest English literature is poetical; and from the days of Caedmon down to our own time, the typical characters of landscape have found reflection in our national poetry. It is not merely from what are called descriptive poems that information of the kind required is to be gathered. The wild border-ballad, full of the rough warfare of the time, has a background of bare moorland, treacherous moss-hags, and desolate hills, which can be compared with the aspect of the same region to-day. The gentler lyrics of a later time take their local colouring from the glades and dells, the burns and pastures where their scenes are laid. In the stately cadence of the Faery Queen, among the visionary splendours of another world, the rivers of England and Ireland are pictured, each with its characters touched off as they appeared in the days of Elizabeth. And in Drayton's quaint, but somewhat tiresome Polyolbion, abundant material is supplied for a comparison between the topography of England at the beginning of the seventeenth century and that of our own time.[3]
But these comparisons have still to be worked out. As an example of the kind of use that may be made of them, and of the light which our poetry may cast, not only upon physical changes, but upon historical facts, I would refer to the passages in Barbour's poem of The Bruce descriptive of the Battle of Bannockburn.[4] I do not contend for the complete historical veracity of the Archdeacon of Aberdeen, though I think he hardly deserves the sweeping and contemptuous condemnation meted out to him by J. R. Green. As he was born only some two years after the battle, as he had travelled a good deal, and as the field of Bannockburn lay across the land-route from the north to the south of Scotland, we may believe him to have made himself personally acquainted with the ground. At least, he could easily obtain information from many who had been themselves actors in the fight. He had no object to gain by drawing on his imagination for the local topography, more especially as his little bits of local description were not in any way required for the glorification of his hero. I think, therefore, that when Barbour describes a piece of ground, we may take his description as a fairly accurate representation of the topography, at least in his own day; and the scene could hardly have changed much in the generation that had passed since the time of Bruce. Now, many persons who have visited the site of the Battle of Bannockburn have felt some difficulty in understanding why the English army did not easily outflank the left wing of the Scots. At present, a wide fertile plain stretches for miles north and south on the east side of the low plateau on which Bruce's forces were drawn up.[5] A small body of the English cavalry did, indeed, make its way across this plain until overtaken and cut to pieces by Randolph. But why was this force so easily dispersed, and why was no more formidable and persistent effort made to turn that left flank? It is very clear that, had the topography been then what it is now, the Battle of Bannockburn must have had a far other ending.
The true explanation of the difficulty seems to me to be supplied by some almost casual references in Barbour's account of the operations. He makes Bruce, in addressing his followers, allude to the advantage they would gain should the enemy attempt to pass by the morass beneath them. The poet further narrates how the Carse, that is, the low flat land on the left, was dotted with pools of water: how the English, in order to effect a passage, broke down houses, and tried to bridge over these pools with doors, windows, and thatch from the cottage roofs; and how, with the assistance of their compatriots in Stirling Castle, they were so far successful that Clifford's troop of horse, and, possibly, some more of the English army, got safely over to the hard ground beyond. We thus learn that Bruce's famous device of the 'pots' was only an extension of the kind of defence that nature had already provided for him. The ground on his left, now so dry and so richly cultivated, was then covered with impassable bogs and sheets of water; and the huge army of Edward was consequently compelled to crowd its attack into the narrow space between these bogs and the higher grounds on Bruce's right.
(2) Another wide field of inquiry for information touching changes in the aspect of the country is supplied by the etymology of place-names. These names, at least those of them that date from old times, possess a peculiar value and interest as abiding records of the people who gave them, and also, in many cases, of the circumstances in which they were given. We are at present concerned only with those that embody some physical fact in the topography. Many of these are as appropriate now as they were at first; for the features to which they were applied have remained unaltered. Ben Dearg shows the same red slopes that struck the earliest Celtic tribes who looked up to it from the bays and glens of Skye. The big stones on the summit of Penmaenmawr still stand as memorials of the British people who erected them and gave their name to the hill.
But in innumerable instances the appositeness of the designation has been lost. The name has, in fact, been more permanent than the feature to which it is applied. The one has survived in daily speech from generation to generation: the other has wholly passed away. By comparing the descriptive epithet in the name with the present aspect of the locality, some indication, or even, perhaps, some measure of the nature and amount of the changes in the topography, may still be recovered.
Now in researches of this kind the liability to blunder is so great, and many able writers have blundered so egregiously, that the inquiry ought not to be entered upon without due preparation, and should not be continued without constant exercise of the most scrupulous caution. The great danger of being betrayed into error by the plausibilities of phonetic etymology should never for a moment be lost sight of. Where possible, the earliest form of the name should be recovered, for in the course of time local names are apt to be so corrupted as to lose all obvious trace of their original orthography.
The Celtic place-names[6] are as a whole singularly descriptive. The Celtic tribes, indeed, have manifested, in that respect, a keener appreciation of landscape and a more poetical eye for nature than their Saxon successors. Who that has ever stood beneath the sombre shadow of the cloud that so often rests on the shoulder of the Grampians will fail to recognise the peculiar fitness of the Gaelic name for the highest summit of the chain—Ben-na-muig-dubh, 'the mountain of dark gloom'? Or who has ever watched the Atlantic billows bursting into white foam against the cliffs of Ardnamurchan and did not acknowledge that only a poetic race could have named the place 'the headland of the great ocean.' The colours of mountain and river have been seized upon by these people as descriptive characters that have suggested local names. Swiftness and sluggishness of flow have furnished discriminating epithets for streams. Moors, forests, woodlands, copses, groups of trees, solitary bushes, lakes, mosses, cliffs, gullies, even single boulders, have received names which record features in the landscape that struck the imagination of the old Celt, and which are still in use, even when the features that suggested them have long vanished out of sight. From this source glimpses may be had of the character of the vegetation and of the wild animals in prehistoric times. Thus we learn that the desolate, treeless tract of Ross-shire known as the Dirriemore (great wood) must once have been clothed with forest. How numerous wild boars were in the country is shown by the frequent occurrence of the name of the animal (Torc, turk) in local topography. The former haunts of the wolf are indicated by its Gaelic appellation (madah, maddie) in Highland place-names. Many descriptive names which have never found a place on any map are well known to the Welsh and Gaelic-speaking inhabitants, who in the more mountainous and trackless regions have often a wonderful acquaintance with the details of the topography.