Page:1902 Encyclopædia Britannica - Volume 26 - AUS-CHI.pdf/711

 CHANNEL

TUNNEL

655

formation of the Submarine Continental HailwTay Company, and, since at the same time the Channel Tunnel Company was resuscitated and made an application to Parliament, there were two rival schemes for making a tunnel from the English shore to join the French company in the middle of the Channel. The Submarine Railway Company proposed that its tunnel should start from the west of Dover, close to Shakespeare Cliff, and the Channel Tunnel Company selected Fan Hole for its starting-point instead of St Margaret’s, as in its former scheme. «. The whole question was then widely discussed from various points of view and considered by several committees, the last of which—a joint select committee of the House of Lords and House of Commons—in 1883 expressed the opinion, although not unanimously, that it was “not expedient that Parliamentary sanction should be given to a submarine communication between England and France.” This decision prevented the carrying out of the enterprise by the English companies, and led to the formation of an amalgamated Channel Tunnel Company, which is still in existence and ready to act should Plan of Proposed Channel Tunnel. opportunity occur. The the same strata of chalk whicb plunge under the sea in operations of the French company were also stopped, England reappear in the cliffs of France, and their con- and it too awaits a reconsideration of the question by tinuity underneath the Channel was shown by samples Parliament. The physical characters of the rocks on both sides of the obtained from the bed of the sea. The next step was the appointment of an international committee, which con- Strait are singularly well adapted for a tunnel from an cluded that there was a reasonable prospect that the work engineering point of view. could be done, and saw no reason to assume that its cost rocks exposed in the cliffs between Folkestone and St would exceed ten millions sterling. The French Government, Margaret’s, measured for the purposes of the proposed tunnel, are accepting the scheme, in 1870 made a formal application as follow, in descending order :— Thickness. for the views of the British Government, but the negotiaEnglish Feet. VI. St Margaret’s Chalk . . . 280 tions were broken off by the Franco-German war. They V. Nodular Chalk with flints. . . 100 were renewed in 1871, and as a result the British Govern- Upper { IV. Chalk with few flints .... 100 ment intimated that it had “ no objection in principle ” to Middle. III. Lower White Chalk with nodular layers, without flints ..... 145 the tunnel. After some further communications between II. Grey Chalk and Chalk Marl (No. II. of the two Governments in 1874, settling the basis on which Lower. Price) 225 the enterprise should be allowed to proceed, a joint I. Glauconitic Marl (No. I. of Price). . 3 commission was appointed to arrange details relating to Gault 120 jurisdiction, the right of blocking the tunnel, &c., and this The Gault, a stiff blue impervious clay, forms a low line of commission’s report was accepted by the Treasury as a cliffs on the west side of Eastwear Bay, and disappears beneath basis of an agreement between the two Governments. In low-water mark, opposite the western end of the Abbotscliffe. It consequence of these negotiations two companies were occurs in St Margaret’s Bay at a depth of 536 feet below O.D. formed. The French company received its concession in The Glauconitic Marl, No. L, a clayey calcareous eposit, generimpervious, but sometimes so full of grains of glauconite and 187 5, and the English Channel Tunnel Company, which had ally sand as to be pervious, overlies the Gault and passes into the applied to Parliament for leave to construct preliminary Chalk Marl underlying the Lower Grey Chalk, No. II. This sets works at St Margaret’s, obtained its Act in the same year. in in the cliff traversed by the Folkestone tunnel at 360 feet The French Submarine Railway Company at once under- above O.D., and descends to Ordnance datum a little to the east Shakespeare Cliff. It constitutes the base of the cliff from took costly preliminary operations, obtaining over 3000 of Abbotscliffe as far as that point. From this as far as the samples of the bottom of the sea in the Strait, and taking west base of Eastcliffe, the cliffs are composed of the Middle more than 7000 soundings, which have rendered it possible Chalk Nodular, and White, No. III., rising on the west to 490 + to map the range of the chalk of the sea bottom with the O.D., and plunging down to the east to a depth of- 180 O.D. at Margaret’s. At its base is a hard nodular iron-stained layer, same accuracy as in the cliffs. The shaft at Sangatte was St the Grit-bed of Price (the Melbourne Rock of the English Geosunk and the heading begun, in faith in the understanding logical Survey), forming a conspicuous band in the English arrived at between the two Governments. The English and French cliffs. The three upper members of the section concompany was unable to obtain the necessary capital, stitute the Upper Chalk, out of which the cliffs between Dover St Margaret’s have been carved. All these strata dip owing to commercial depression, and its powers lapsed in and steadily to the east at an inclination of about 1 in 72. On the 1880. The South-Eastern Railway had obtained powers French side, in the cliffs between St Pot and Sangatte, the Lower in 1874 to sink experimental shafts on their property and Middle Chalk of the English section emerge from the sea with between Dover and Folkestone, and in 1881 to acquire physical characters the same, and the thickness practically also same. They dip also to the east, but at an angle of 1 in 46. lands, including the beach and foreshore, in that area the The French survey of the sea bottom in the Strait for the purfor experimental works in connexion with the construction poses of the proposed tunnel proves that the Lower and Middle of a Channel tunnel. These resulted, in 1882, in the Chalk are perfectly continuous and constitute the sea floor, the half a mile west of the South Foreland Light, and on the French shore Sangatte, about four miles to the west of Calais, as the ends of the tunnel. Between these two points he considered galleries could be made entirely through the Dover Grey Chalk, which, owing to its comparative freedom from water and the general absence of cracks and fissures, offered exceptional facilities for work. Mr Low laid his plans before the Emperor of the French in 1867. Sir John Hawkshaw had also considered the question of a tunnel, and decided to make two borings at the ends of the line which seemed approximately the best position, and to examine the bottom of the Channel for some distance on each side of that line. In the year 1866 borings were begun at St Margaret’s Bay and near Sangatte (see A on plan); these proved that