The Compendium of Caraka 4.8.10_1

4.8.10_1

tāṃ paścimenāhatavastrasaṃcaye śvetārṣabhe vā'apyajina upaviśed brāhmaṇaprayuktaḥ, rājanyaprayuktastu vaiyāghre carmaṇyānaḍuhe vā, vaiśyaprayuktastu raurave bāste vā/

To the west of it, employed by a brāhmaṇa, he should sit upon a heap of intact cloth or on a white bull's hide; employed by a kṣatriya, on a tiger skin or an ox skin; employed by a vaiśya, on a ruru-deer skin or a goat skin.