《尚书·夏书·禹贡》
这州的土是白壤，赋税是第一等，也夹杂着第二等，这里的田地是第五等。
厥土惟白壤，厥赋惟上上错，厥田惟中中。
The soil in this province is white clay, it is taxed as the first grade but there is also some second grade, and the fields are taxed as the fifth grade.