Pṛthivy-Āyāma-Vistara (Extent of the Earth) and Jambūdvīpa–Navavarṣa Description
तेनास्य शूद्रभावः स्यादिति वर्णाः प्रकीर्त्तिताः / वृत्तः स्वभावतः प्रोक्तो वर्णतः परिमाणतः
tenāsya śūdrabhāvaḥ syāditi varṇāḥ prakīrttitāḥ / vṛttaḥ svabhāvataḥ prokto varṇataḥ parimāṇataḥ
Thus it is said that in him the state of a Śūdra arises—so have the varṇas been proclaimed. His form is spoken of by innate nature, and his measure is determined by color.