Shiva Purana
विप्रक्षत्रियवैश्यास्ते शूद्राश्च मुनिसत्तम ॥ कल्पवृक्षसमानस्तु तन्मध्ये सुमहातरुः ॥ ३० ॥
O excellent sage, there are brahmins, Kṣatriyas, Vaiśyas and Śūdras there. In its middle there is a big tree like the celestial Kalpa tree.
english translation
viprakSatriyavaizyAste zUdrAzca munisattama ॥ kalpavRkSasamAnastu tanmadhye sumahAtaruH ॥ 30 ॥
hk transliteration by Sanscript