Greek writings as well archaeological excavations indicate the existence of an urban economy dependent on agriculture and trade in the Indus basin. The Greeks mention the existence of cities and fortified towns such as Taxila. Arrian mentions that after defeating Porus, Alexander marched eastwards towards the Chenab River, and captured 37 towns: the smallest of these towns had 5,000 or more inhabitants. In the Swat valley, Alexander is said to have seized 230,000 oxen (possibly Zebu), intending to send them to Macedonia for ploughing land. Aristobulus saw rice being grown in paddy fields, Onesicritus reported the existence of a crop called bosmoran (possibly the pearl millet), and Nearchus wrote of honey-yielding reeds (presumably the sugarcane). Nearchus also mentions that Indians wore clothes made of cotton. Rock salt was extracted from the Salt Range, and supplied to other parts of India. Some primitive communities existed in the forest, desert, and coastal regions of the subcontinent. For example, Nearchus mentions that people around the Tomeros river (Hingol) subsisted on fishing, and used stone tools instead of iron ones.