《南齐书·志·卷九》
郑玄说 祭地是阴祀，用黑色牲畜，与祭天一样都用牛犊，所以连在一起说了 由此可知这里祭祀天地就是南北郊祭。
郑云 地，阴祀，用黝牲，与天俱用犊，故连言之耳 。知此祭天地即南北郊矣。
Zheng Xuan said that the sacrificial offering to the earth was a cult to the underworld, using black sacrificial animals, and just like the sacrificial offering to heaven, it also used young bulls, that's why it was mentioned together. From this we can know that the sacrificial offering to heaven and earth here was the north and south郊 sacrificial offering.