A long, high mountain range extends all along the western frontier, from the far north down through muranymianiad the Malay peninsula. The extreme northern province, Monton Payap, is hily throughout, but especially in rešyalnai Geeanends áyriuraaa utwhima the Chieng Mai region, where some peaks are over six thousand feet high. muniguiu wn 2-3 sou 1ianf Solau. Wmo Pnnnoconádn: ne. Eastern Siam is mostly a plateau, with an elevation of a few hundred feet; and central Siam a low- lying plain, which slopes very gently south-southeast to the Gulf of Siam.