Page:Provincial geographies of India (Volume 4).djvu/78

62 The so-called "mud volcanoes" of Cheduba Island, Minbu and other places are of a totally different category and origin. They are not volcanoes in the correct sense of the term, but mere ejections of salt mud thrown out by the force of hydrocarbon gases and frequently accompanied by petroleum. They are, in fact, nothing more than the accompaniments of gas seepages, and are intimately associated with occurrences of oil. Through the stopping up of the vents, these mud eruptions are sometimes of explosive violence, and the friction of colliding stones with one another may set fire to the inflammable gas, producing a result still more closely resembling the fiery eruption of a true volcano. This has happened more than once in the case of the large "mud volcano" in the island of Cheduba off the Arakan coast.

The Tertiary plateau, as well as the higher-lying Shan plateau, is covered with a mantle of red clayey silt which passes here and there into a deposit of gravel. The still more recent clays and sands, which have produced and are still producing the deltas of the Irrawaddy and Sittang, constitute part of the last-written and still incomplete chapter in the history of Burma. What the end of this chapter will be and what other chapters will follow, who would dare to say?