ARAVALLI HILLS, an Indian mountain range; running for 3oom. in a north-easterly direction, through the Rajputana states and the British district of Ajmere-Merwara, situated be tween 24° and 27° N., and between 72° and 75° ,5° East. The series of ridges and peaks, with breadth varying from 6 to 6om., are generally from 1,000 to 3,000ft. in elevation, the highest point, Mount Abu (5,65oft.), being in the extreme south-west. Geologi cally they belong to the primitive formation characteristic of the Indian Deccan-granite, compact dark blue slate, gneiss and sye nite. Masses of rose-coloured quartz give a dazzling snow-like appearance to the peaks. The Luni and Sakhi rivers, from the steep north-western slopes, turn south-west to the Gulf of Cutch. Two distinct river systems drain the south-eastern slopes; one debouches in small streams on the Gulf of Cambay, while the other unites to form the Chambal river, a tributary of the Jumna and the Ganges system. The Aravalli hills are for the most part bare and thinly populated, with large areas of sand and stone, or huge masses of quartz. The valleys are generally sandy deserts, with sparse oases of cultivation. Occasionally, however, a fertile tract marks a natural drainage line, e.g., that of Ajmer city, with its lake. The Aravalli hills send off rocky ridges north-east through the states of Alwar and Jaipur, which reappear in the form of isolated hills near Delhi.