D URING My Visit to This Locality, the Time at My Disposal Did Not
Total Page：16
File Type：pdf, Size：1020Kb
Downloaded from http://trngl.lyellcollection.org/ at UQ Library on July 12, 2015 BARR—NORTH-EASTERN DISTRICT OF YORKSHIRE. 291 XXYI.—On the GEOLOGY of the NORTH-EASTERN DISTRICT of YORKSHIRE. By THOMAS M. BARR, C.E. (Read 13th March, 1873.) DURING my visit to this locality, the time at my disposal did not allow me to make anything like a systematic or exhaustive study of its geology. But seeing that its geological features differ so widely from those of our own district, while its iron products give it a peculiar interest, a few notes upon it may not be unacceptable to the members of this Society. The district which I propose to include in this description is that lying between the Tees and Eskdale. The map of the Geological Survey not being yet published, I have prepared one on which the leading geological features of the district are shown. Perhaps the first thing which strikes a visitor from the Scotch iron districts is the absence, in Cleveland, of igneous rocks, with their consequent upheavals and disturbance of strata. On the north of the Eston Hills, and along the track of the North-Eastern Railway from Darlington to York, the country is generally very flat; but to the east of this line, between Eston and Whitby, it is in many parts exceedingly picturesque. The surface is undulating, but it seldom exceeds a height of from 600 to 800 feet above the sea. " Roseberry Topping," about 3 miles south-west from Guis- borough, which forms the most prominent point in the district, is 1022 feet, and " Eston Nab " is 784 feet above the sea. The coast from Middlesborough to Redcar is very flat for a breadth of one to two miles inland. South of Redcar it begins to rise towards Marske and Saltburn-by-the-Sea, where it reaches a height of from 150 to 200 feet, and thence to Whitby it presents bold escarpments, except at those places where a stream has worn down a channel and formed a bay at its mouth. The highest cliff is near Boulby, and is 680 feet in height. These cliffs consist of numerous beds of limestone, sandstone, and shale, varying in thickness from a few inches to two or three feet, and, from their composition, being very ill adapted to resist the encroachments of the sea and the action of the weather, they are being eaten away much more rapidly than the cliffs on our Scottish coasts. There is a constant falling of loose materials, and Downloaded from http://trngl.lyellcollection.org/ at UQ Library on July 12, 2015 292 TRANSACTIONS OF THE GEOL. SOC. OF GLASGOW. it is therefore advisable to give them a wide berth when walking along the shore. At the base, in the more exposed parts, the shore consists of rough irregular shingle, the debris from the cliffs, which, being subjected to the action of the waves, is ground down to sand and carried into the bays, where it forms the beautiful sandy beaches seen at Scarborough, the north shore at Whitby, and the fine promenade extending from Saltburn to Redcar, about five miles in length, and nearly half a mile in breadth at low water. Geologically speaking, the whole of the strata are comparatively new, none of them going further back than the Mesozoic period. At the river Tees on the North, which separates the counties of York and Durham, the Trias beds are found underlying the Lower Lias shales of the surface. A bore was put down at Coatham, near Redcar, in 1867, and at a depth of 56 fathoms the new red marl was found. The classification of the Triassic system is— {Rhoetic Beds. KKUPER, -JNew Bed MarL VLower Keuper Sandstones. MTJSGHELKALK—Not represented in this country. /Upper Mottled Sandstone. BUNTER, < Pebble Beds and Coarse Bed Sandstone. 'Lower Mottled Sandstone. The Middlesborough beds are all considered to belong to the New Red Marl of the Keuper, leaving the other beds still unproved as yet. The system is more completely developed in Cheshire, where it has been carefully examined by Mr. Ormerod, and tabulated as under:— (New Red Marl, 700 feet thick KEUPER, •} Lower Keuper, 400 BUNTER,—Sandstones and Conglomerate, 600 „ Total, .... 1700 feet. In Yorkshire it is not so easy to get at the beds, as they underlie the lias shales, and are not exposed in cliff sections as in the west. Mr. John Jones, F.G.S., has devoted much attention to them, and has contributed many valuable papers on the geology of the district. From observing the outcrop of the Magnesian limestone in Durham (which is a curved line by Pierce Bridge, Simpasture, Sedgefield, Southwingate Colliery, to the sea between Hartlepool Downloaded from http://trngl.lyellcollection.org/ at UQ Library on July 12, 2015 Downloaded from http://trngl.lyellcollection.org/ at UQ Library on July 12, 2015 BARE—NORTH-EASTERN DISTRICT OF YORKSHIRE, 293 and Sunderland), and the dip of the beds in Cleveland, he estimates there must be a thickness of 2640 feet of Triassic beds there. So far as yet proved, they are referred to the New Red Marl, and have been examined to a depth of 1306 feet. If the other beds of the Cheshire Section are represented at Middlesborough, and are the same thickness as in Cheshire, it would give a total thickness of 2306 feet, agreeing very nearly with Mr. Jones' calculation. A very important circumstance connected with the Triassic beds was the discovering, about nine years ago, of a deposit of rock salt under the works of Messrs. Bolckow & Vaughan, Middlesborough, when sinking a bore for water. This deposit was supposed to be upwards of 100 feet thick, and was proved over a considerable area. An idea was first entertained of pumping it up in the form of brine, but this was found to be impracticable, and the sinking of two shafts was commenced about the end of 1869. In February, 1870, these were down 75 feet, and in March, 1871, 309 feet. The New Limited Liability Company set aside £40,000 for this work, but operations were suspended about six or eight months ago, the company probably having found that their capital can at present be better employed in the iron manufacture. The upper beds of the Keuper are also worked for gypsum, near Lackenby and Eston Station. Above these Triassic beds we have the alternating shales and limestones of the Lower Lias. These are found in the low-lying ground before referred to, between the Tees and the Eston Hills, running out seawards at Redcar. It may here be remarked that the strata throughout the district present very little appearance of disturbance or contortion. They are generally found in a position approaching very nearly to the horizontal, and the fineness and regularity of the lamination would indicate that they have been deposited in tranquil seas. I have a small specimen, picked up on the shore, which is a beautiful model of a cliff in miniature. There are fifty-six distinct layers in an inch of its thickness, all perfectly regular and parallel, and the action of the water has worn away the softer beds, leaving the harder ones projecting exactly as is seen on a larger scale in the cliffs. There is a basaltic dyke extending about sixty miles from beyond Cockfield Fell, in Durham, in an east-south-east direction, to the neighbourhood of Sneaton, where it terminates rather Downloaded from http://trngl.lyellcollection.org/ at UQ Library on July 12, 2015 294 TRANSACTIONS OP THE GEOL. SOC. OF GLASGOW. obscurely. There is also a dislocation in the line of the harbour at Whitby, the strata on the western side being about 150 feet below the corresponding strata on the eastern side. The Middle Lias forms the lower portions of the hills, and includes the " Main Seam" of the Cleveland ironstone, the most important deposit of the whole system. It also forms the bottoms of many of the valleys scooped out by the streams. The Cleveland ironstone crops out on the north slope of the Eston Hills, a short distance south of the Tees, and extends southward to near Thirsk, occupying great part of the district lying between the sea and the main line of the North-Eastern Railway, an area of some hundreds of square miles. The " Main Seam" was discovered by the late Mr. Vaughan in the Eston Hills in 1850, and this may be said to have started the Cleveland iron trade, for although iron was known to exist in the district, and several beds of nodular iron stone had been worked before that time, it was only in an irregular manner, and on a small scale. In 1835 Professor Phillips wrote of the ironstone that "at present it is of no value but as ballast/' and now the district produces about one-third of the total pig iron made in this country. It may be interesting here to give a few figures to show the magnitude and rapid growth of this branch of industry, taken from the returns of the Cleveland Iron Masters' Asssociation for 1872: Make of Pig Iron in 1868, - - - 1,233,418 tons. 1869, - - - 1,459,508 „ 1870, - - - 1,695,377 „ 1871, - - - 1,884,239 „ 1872, - - - 1,968,972 „ At the close of the year there were in the district 137 blast furnaces, 130 of which were in blast, and 16 new ones have been erected during the past year. The average product of a furnace is 400 tons per week. The raw material used per annum is in round numbers— Ironstone, 5,000,000 tons.