THE Survey of India topographical sheet 54C, Sawai Mad-hopur, scale 4 miles to 1 inch (first published in 1908), shows a latitude 25° 20′; N, longitude 76° 37′ 30″ E, an isolated hill of annular shape, forming an almost complete circle approximately 3 km in external diameter. This feature lies in eastern Rajasthan almost on the boundary with Madhya Pradesh, approximately 350 km SSW of New Delhi and approximately 13 km east of the small town of Mangrol1. It is east of the Parbati river on the interfluve between it and a right bank tributary, the Kul. The country there is almost flat, and although the region lies within the general outcrop of the upper Precambrian Vindhyan System, the bedrock is almost entirely obscured by a wide belt of alluvium. Where Vindhyan rocks are exposed in the vicinity, as in the bed of the Parbati river 6 km east of Mangrol, they are flat-lying and undisturbed.