《水经注·卷二十二》
颖水流经岔高县旧城南边，从前舜让位给禹，禹避让商均，伯益又避让启，都是在这里；这里也是周公用土圭测日影的地方。
颀水径其县故城南。昔舜禅禹，禹避商均，伯益避启，并于此也。亦周公以上圭测日景处。
The Ying River flows past the south of the old city of Chagao County. Shun once yielded to Yu, Yu avoided Shangjun, and Boyi avoided Qi, all of which happened here. This is also where Duke Zhou used a sundial to measure the sun's shadow.