Samuel White Baker - The Rifle and the Hound in Ceylon стр 16.

While describing the long shots performed by this particular rifle, I cannot help recounting a curious chance with a large rogue elephant in Topari tank. This tank or lake is, like most others in Ceylon, the result of vast labour in past ages. Valleys were closed in by immense dams of solid masonry, which, checking the course of the rivers, formed lakes of many miles in extent. These were used as reservoirs for the water required for the irrigation of rice lands. The population who effected these extensive works have long since passed away; their fate is involved in mystery. The records of their ancient cities still exist, but we have no account of their destruction. The ruins of one of these cities, Pollanarua, are within half a mile of the village of Topari, and the waters of the adjacent lake are still confined by a dam of two miles in length, composed of solid masonry. When the lake is full, it is about eight miles in circumference.