Canto 3 -
Araṇya-kāṇḍa
Chapter 56: Sītā is Taken to Aśoka-vana
Text 3.57.18

न शक्या यज्ञमध्यस्था वेदिः स्रुग्भाण्डमण्डिता।
द्विजातिमन्त्रपूता च चण्डालेनावमर्दितुम्॥

na śakyā yajña-madhyasthā vediḥ srug-bhāṇḍa-maṇḍitā
dvi-jāti-mantra-pūtā ca caṇḍālenāvamarditum

na śakyā = it is not meant; yajña-madhyasthā = in the center of a sacrificial arena; vediḥ = a large sacrificial platform made of bricks; srug-bhāṇḍa-maṇḍitā = is decorated with ladles and pots; ca = and; dvi-jāti-mantra-pūtā = purified by mantras from the twice-born; caṇḍālena = by a caṇḍāla; avamarditum = to be trampled upon.

A large sacrificial platform made of bricks in the center of a sacrificial arena is decorated with ladles and pots, and purified by mantras from the twice-born. It is not meant to be trampled upon by a caṇḍāla.