Margaret's Bay, in Kent, for the purpose of going ahead with experimental tunneling work there. At the same time, a newly formed French Channel Tunnel Company backed by the House of Rothschild and headed by an engineer named Michel Chevalier obtained by act of the French legislature permission from the French Government to start work on a tunnel from the French side at an undetermined point between Boulogne and Calais, and a concession to operate the French section of the tunnel for ninety-nine years. The _cahier des charges_ of the French tunnel bill dealt in considerable detail with the terms under which the completed tunnel was to be run, down to providing a full table of tariffs for the under-Channel railroad. Thus, a first-class passenger riding through the tunnel in an enclosed carriage furnished with windows would be charged fifty centimes per kilometre. Freight rates were established for such categories as furniture, silks, wine, oysters, fresh fish, oxen, cows, pigs, goats, and horse-drawn carriages with or without passengers inside. The greatest uncertainty facing the two companies, now that they had the power to start digging toward each other's working sites, consisted of their lack of foreknowledge of geological obstacles they might encounter in the rock masses lying between the two shores at the neck of the Channel. However, the companies' engineers had substantial reasons for believing that, in general, the region and stratum into which they planned to take the tunnel were peculiarly suited to their purpose. Their belief was based on a rough reconstruction—a far more detailed reconstruction is available nowadays, of course—of various geological events occurring in the area before there ever was a Channel. A hundred million years ago, in the Upper Cretaceous period of the Mesozoic era, a great part of southern England, which had been connected at its easterly end with the Continental land mass, was inundated, along with much of Western Europe, by the ancient Southern Sea. As it lay submerged, this sea-washed land accumulated on its surface, over a period of ten million years, layers of white or whitish mud about nine hundred feet thick and composed principally of the microscopic skeletons of plankton and tiny shells. Eventually the mud converted itself into rock. Then, for another forty million years, at just the point where the neck of the Dover Strait now is, very gentle earth movements raised the level of this rock to form a bar-shaped island some forty miles long. By Eocene times this Wealden Island, stretching westward across the Calais-Dover area, actually seems to have been the only bit of solid ground standing out in a seascape of a Western Europe inundated by the Eocene sea. When most of France and southern England reappeared above the surface, in Miocene times, this island welded them together; later, in the ice age, the Channel isthmus disappeared and emerged again four times with the rise and fall of the