48 Correspondence. 



COEEESPOIsriDElTCB. 



DEEP-BOEING IN PEUSSIA, etc. 



Sir, — It may interest some of the readers of the Geological 

 Magazine to learn that a boring has lately been carried out by the 

 German Government at Sperenberg, twenty-five miles south of 

 Berlin, which has reached the surprising depth of 4040 feet ! and 

 is the deepest boring in the world (not even excepting America) ! 

 It is almost all through the Saliferous Bocks, Triassic series (Keuper, 

 Muschelkalk, and Bunter), and was finished in 1872. The boring 

 is done with rods, but the details I have not yet learned. 



The following Extract from a letter, 19th Nov., 1874, from 

 Thos. J. Bewick, Civil and Mining Engineer, to Major Beaumont, 

 M.P., Managing Director, Diamond Bock-Boring Company, Limited, 

 2, Westminster Chambers, London, may prove of interest, as 

 showing what can be done by means of Diamond Boring. 

 " Bohemian Broad-Bore-Hole. 



" Actual boring was commenced on the 15th July last. On 8th 

 inst. the depth was 1931 Vienna feet, equal 2001 4" English feet. 

 At commencement bored 35 feet, when stopped by fall of ground. 

 13' more, equal to 48', lined with 5 inch tubes, and then bored up to 

 96 feet with 4 inch crown. Lost water by a cleft at 73 feet. Bored 

 to 180 feet with 4 inch crown. Again lost water from tubes not 

 being close to the bottom. Withdrew 96 feet of tubes, and widened 

 the whole to 180 feet with 5 inch crown. Lined with 5 inch tubes 

 to that depth, and continued with 3 inch crown to bottom. No 

 more tubes required after 180 feet. Usual recent rate of boring 30 

 to 40 feet per day of 24 hours (2 shifts of 12 hours each). Boring 

 is in New Bed Sandstone formation. Conglomerate occurred from 

 520 to 580 feet, 680 to 850 feet, and 1200 to 1510 feet, equal to 

 540 feet in all. The pebbles were firm, with but few loose stones. 

 The Conglomerate consists of porphyry, Silurian shales, granite, and 

 quartz. The rest of the strata are the usual Sandstones, Shales, and 

 Marls in the New Bed Sandstone formation." 



I can only hope the Sub-Wealden Exploration may succeed in 

 attaining as great a depth as that of Sperenberg, near Berlin. — J. P. 



ENGLAND AND FEANCE IN THE GLACIAL EPOCH. 



g IB} — In a clever and able article by Mr. Thomas Belt, E.G.S., 

 published in the "Quarterly Journal of Science" for October last, 

 that gentleman advocates the theory of a great river flowing south- 

 wards, towards the close of the Glacial epoch, down what is now the 

 English Channel, and embracing the Bhine, the Thames, the Seine," 

 and other rivers in its course. 



This is, I believe, contrary to the generally received notion that 

 the Straits of Dover had not then been cut, and that the Thames 

 flowed northwards to join the Bhine. 



Perhaps Professor Prestwich or some other of your Quaternary 

 Geological readers will relieve my mind by telling me which is the 

 right faith. J. Sussex. 



