The affix yat comes in the sense of 'in it is visible' after the word pada being in the Nominative 1st-Case in construction.,
Thus पद दृश्यमस्मिन् = पद्यः कर्दम 'mud' lit. soft mud in which foot-mark can be seen at every step. It describes mud which is neither very hard nor very fluid, but having sufficient consistency to take the impression of the foot. So पद्याः पांसवः 'dust' for in it also the impression of the foot can be seen. It also means 'the foot-path.' The word दृश्यम् means शक्यते द्रष्टुम् this being the force of the kritya affix 'ya' in दृश ॥,