Page:Encyclopædia Britannica, Ninth Edition, v. 24.djvu/548

Rh 514 WESTMORLAND Brough ; Haikable, or High Cup Gill, near Appleby ; Orton Scars ; and the limestone crags west of Kirkby Lonsdale. Amongst the waterfalls are Caldron Snout, on the northern confines of the county, flowing over the Whin Sill, and Stock Gill Force, Eydal Force, Colwith Force, and Dungeon Gill Force, all situated amongst the volcanic rocks in the west. Hell Gill, near the head of the Eden, and Stenkrith, near Kirkby Stephen, are conspicuous examples of natural arches eroded by the streams flowing through them. Amongst the more striking hills outside the massif of the Lake District are Wilbert Fell, Roman Fell, Murton Pike (1949 feet), Dufton Pike (1578 feet), and Knock Pike (1306 feet). Geology. The geological formations represented iu Westmor land are : (A) (1) recent deposits, and (2) glacial drift ; (B) New Red rocks (1) Upper New Red, and (2) Lower New Red or Permian ; (C) Carboniferous rocks (1) Coal-Measures and Millstone Grit, (2) Yoredale Rocks and Mountain Limestone, including the Roman Fell beds, Calciferous Sandstones, and the Lower Limestone Shale, and (3) the Upper Old Red ; (D) Siluro-Cambrian rocks (1) Silurian rocks proper, (2) Upper Cambrian, Ordovidan or Lower Silurian rocks, and (3) Cambrian rocks ; (E) Metamorphic rocks of different ages ; and (F) various Plutonic rocks. Alluvium in some form or another occurs as marginal deposits alongside streams, or as deltas where streams enter lakes, or where they spread at the foot of a hill-side. Peat forms a mantle of varying thickness on the damper or the more shady parts of nearly all the uplands, ranging locally up to a thickness of 10 feet, and occurs on the sites of old tarns or of old swamps. Screes of rock waste ara of general occurrence about the lower parts of nearly all the crags, and as such they play an important part in the scenery of the district. Glacial deposits, in the form of boulder clay, of sand and gravel, or of boulders, are extensively distributed over the lowlands, and to a variable distance up the hill-sides also. They seldom much exceed 100 feet in thickness ; but their occur rence is of considerable importance in relation to the scenery, and still more so to the character of the subsoil. Boulders of various kinds are scattered far and wide over nearly all but the highest parts of the county. Between the period represented by the boulder clay and the next older deposit in Westmorland a great hiatus exists, which is else where represented by several very important geological formations. Here the newest rock next in the series is the St Bees Sandstone and the gypseous shales at its base, which together probably re present the Bunter series. These soft red sandstones, flags, and marls with gypsum are all confined to the northern part of the county, where they form much of the low ground extending along the foot of the Cross Fell escarpment from the county boundary east of Penrith south-eastward to Kirkby Stephen. Some of the prettiest scenery of these parts (Crowdundle Beck ; Mill Beck, Dufton ; and Podgill, Kirkby Stephen) owes its character to these rocks. The stone is used extensively for building. Gypsum occurs in workable quantities in the shales near the base. Where fully developed these rocks are not less than 2000 feet in thickness. The next formations in descending order consist of the Magnesian Limestone (0-30 feet), the Helton Plant Beds (0-40 feet), the Penrith Sandstone and its horizontal equivalents the Brockrams (0-1200 feet). All these are older than the rocks previously men tioned, but belong to the same series. They occur in the same tract of country. The highest rocks of the Carboniferous age in Westmorland are represented by a tiny patch of true Coal -Measures, let down, and so preserved from denudation, by one of the great Pennine faults, between Brough and Barras, in north-eastern Westmorland. These rocks consist of several thick and valuable seams of coal, and of beds of fireclay equally valuable, interbedded with several hundred feet of the usual sandstones and shales. 1 True Coal-Measures are not yet known to occur elsewhere in Westmorland. Millstone Grit of the ordinary type underlies these Coal-Measures, and is seen to perhaps a thickness of nearly 2000 feet. Except a small patch exposed near Appleby, and also another near Kirkby Lons dale, the remainder of the Millstone Grit is confined to the higher parts of the wild moorlands along the eastern border of the county. The highest member of the second subdivision of the Carboniferous is the Yoredale Rocks, which form the chief mass of the hills forming the Westmorland part of the great central watershed of northern England. Most of the Cross Fell escarpment, of Stainmoor, and of the higher parts of the valley of the Eden consist of these rocks, as do also much of the lowlands. They consist essentially of a series of thin beds of limestone, parted by variable thicknesses of sandstone and shales, with here and there a thin coal-seam. Their thickness ranges from 1500 to 2500 feet. The Borradale coal-seam, 1 These will be found described in detail in the Trans. Cumb. and West Assoc part vii. pp. 163-177. and the Tan Hill seam, in these rocks, have long been worked for local purposes. Below the Yoredale Rocks limestone preponderates, and the grey limestones of this series form very conspicuous and striking features in the landscape around Kendal, Beetham, and Farletou; Kirkby Stephen, Orton, and Shap ; Brough, llelgill, and Murton, and thence north-westward. Nuar Kirkby Stephen is nearly 2000 feet of this limestone, locally almost undivided. Near Kendal, at Barbon, between Ravenstonedale and Shap Wells, and near Helton occur masses of red gravelly conglomerate and red sandstones belonging to the Upper Old Red. The materials of the conglomerate largely consist of rocks foreign to the district. Fora period of immense length preceding the deposition of the Upper Old Red the older rocks of Westmorland seem to have been exposed to a complicated series of disturbances and denudations, with, as a result, the removal from some areas of a thickness of strata above (rather than below) 5 miles in thickness. It was across the up turned and denuded ends of this vast pile of rock that the Upper Old Red was laid down. The older strata, grouped under D above, are therefore separated from the Upper Old Red by an un conformity representing the removal from this area, and the ac cumulation in some unknown area elsewhere, of a pile of rock 5 miles in thickness. This is one of the greatest breaks yet made known in the whole of the geological record. The Siluro-Cambrian rocks are perhaps more fully developed in Westmorland and Cumberland than they are anywhere else, the aggregate thickness of strata referable to one or other of the hori zons in this group being at least 6 miles. The highest member of this series is the Kirkby Moor Flags, which consist of a considerable thickness of mudstones and sandstones, much disturbed and con torted in places, and form the whole of the low hill country on the east side of the turnpike road between Kendal and Kirkby Lonsdale, and extending thence eastward to a little beyond the Lune. Lithologically and palpeontologically these rocks agree in a general way with the Ludlow rocks of Shropshire. Their highest beds are unconformable to the Upper Old Red, sometimes violently so. These rocks graduate downward into the Bannisdale Slates, 5200 feet of close alternations of flaggy grits and rudely cleaved sandy mudstones. These rocks occupy a large area around Keudal, and to the south-west of that town. They also form a large part of the Howgill Fells. These in turn graduate downward into the Coniston Grits and Flags, which consist of 7000 feet of alternations of tough micaceous grits and rudely-cleaved mudstones, the whole mass tending near its base to pass into finely-striped and cleaved mudstones, the Coniston Flags. The tough and durable nature of the harder beds of this series gives rise to a series of mammillated hills. All the rocks of the series here referred to give rise to a type of scenery different in many essential respects from that result ing from the waste of any other rocks in Westmorland, so that the hill scenery south of a line joining Ambleside and Shap Wells is distinctly different from that to the north of that line. Near their base the argillaceous members of the series graduate downwards into a few hundred feet of pale grey-green inudstoue, with a peculiar porcellanous texture ; and these, in their turn, graduate downwards into a small thickness of pitch-black mudstones, with much the general character of indurated fuller s earth, and usually crowded with graptolites having the general facies of those elsewhere found in the Llandeilo rocks. The pale grey beds are the Stock- dale Beds, or pale slates. &quot; The Graptolitic Mudstones locally have at their base a conglomerate, which consists of rolled fragments of rocks from various horizons in the older series. In general terms these two groups of rocks may be described as occurring along a narrow outcrop extending from near Ambleside to Shap Wells. They reappear also near Dufton and at Cautla. In West morland the Llandovcry beds of Wales appear to be absent, as the rocks next older than the Graptolitic Mudstones consist of rocks characterized by fossils of an unmistakably Bala type. The West morland type of these rocks consists of a mass of alternations of volcanic tuffs and lavas, with the marine equivalents of these, and with limestones and shales, the whole scries thinning as it is traced toward the centre of the Lake District near the head of Windermere. The Coniston Limestone is the best known member of this series. The series as a whole, however, finds its best and most fully- developed representatives outside the area of old subnerial volcanic cones and craters on whose surface the Couiston Limestone lies. The calcareous members of this series are usually replete with well- preserved fossils in great variety. The series under notice forms some conspicuous features along the foot of the Cross Fell escarp ment. Rising from beneath these series just mentioned comes the vast pile of old volcanic ejectamenta, largely subaerial in the typical district, which is known as the Borradale Volcanic Series (see CUMBERLAND). Outside the massif of the Lake District we meet with the submarine equivalents of these subaerial accumula tions. These are well seen at Milburn. They consist of many thousands of feet of alternations of submarine tuffs, with shales and mudstones, seemingly identical in character with the Skiddaw Slates, which in the centre of the Lake District mainly lie at the base of the volcanic rocks. The next type may be described as a