Page:Provincial geographies of India (Volume 4).djvu/64



of the present-day topography of a country would be incomplete without an enquiry into the steps by which that topography had been produced. The contemplation of the coast-line, mountain ranges, valleys, river-systems, fauna, flora and climate of any particular region awakes in us a keen curiosity as to the various changes in configuration and meteorological conditions which have made up the past history of that region. No contemporaneous brain has penned such a history, whose torn and disfigured pages are the rocks from which we try to reconstruct former conditions.

The first chapter of this most ancient book of Nature, in the case of Burma, consists of a belt of gneiss, a quartz-bearing rock which, under the influence of enormous pressure and high temperature, has assumed a banded streaky texture. This belt, commencing near Mandalay, extends northwards and north-westwards through the ruby mines of Mogôk into the country north of Bhamo and into the Chinese province of Yünnan; above Mogôk ranges formed of this gneiss culminate in the Taungme peak (7544 feet above sea-level). Folded up with the gneiss are beds of limestone in which the celebrated Burmese rubies and sapphires are found, but these pages of Burma's geological history are so blotted and blurred that we cannot decipher the conditions under which the limestones and some of the gneiss were produced. The former may represent sediments laid down on an ancient sea-bed, or they may be deposits formed after the consolidation of the surrounding rocks by percolating solutions of carbonate of lime. Some of the gneiss is solidified molten material, but