Ulakhan-Sis

a mountain range in the Yakut ASSR; a continuation of the Polousnyi Ridge. The range extends 160 km from the Indigirka River in the southeast to the source of the Sundrun River in the northeast; it lies between the interfluve of the Ercha and Shandrin rivers in the northwest and the interfluve of the Khatystakh and Arga-Iuriakh rivers in the southeast. Elevations reach 754 m. The range is composed of granites, Devonian sand stones, and extrusive rocks. The valleys have scattered, sparse forests of larch.