Someone who was searching and reached a river, an irrigation canal, or a public highway, stops [his search]. In a field in which people were killed, [if] all the bones are collected the field is then considered tahor. [If] someone is removing a grave from his field, he gathers up every bone and the whole [field] is considered tahor. [Regarding] a pit into which stillborn fetuses or slain people were thrown, the bones are gathered, and the whole [pit] is considered tahor. R’ Shimon says: If [the pit] was initially intended to be a grave, the surrounding earth must be removed.

One who plows a grave thereby creates a beis hapras. How far does [his plowing] make [a beis hapras]? A furrow’s length, which is one hundred cubits, an area of four se’ah. R’ Yose says: An area of five [se’ah]. [This applies] to a downward slope, but on an upward slope [the following procedure determines the size of a beis hapras]: A quarter [kav] of vetch seeds are placed on the knee-shaped part of the plow. Up to the place where three vetches will sprout alongside one another is deemed a beis hapras. R’ Yose says: [The law of beis hapras applies only] to a downward slope, not to an upward slope.

[If a person] was plowing and he struck a rock or a fence, or he shook out the plow, until that point is the beis hapras. R’ Eliezer says: One beis hapras can make another beis hapras. R’ Yehoshua says: Sometimes it does, and sometimes it does not. How so? [If] one plows half a furrow, and then plows the other half or to the sides, this makes another beis hapras. [However, if] he plows a furrow’s length, and then plows from that point on, [the beis hapras] does not make another beis hapras.

[If] a person plows over a pit containing corpses, through a pile of bones, through a field in which a grave was lost, through a [field] in which a grave was [subsequently] found, [or] through [a field] that is not his property, or a gentile plows, it does not make a beis hapras — because [the ruling of] beis hapras does not apply to Cutheans.