Commentary for Bava Batra 7:1
הָאוֹמֵר לַחֲבֵרוֹ, בֵּית כּוֹר עָפָר אֲנִי מוֹכֵר לְךָ, הָיוּ שָׁם נְקָעִים עֲמֻקִּים עֲשָׂרָה טְפָחִים אוֹ סְלָעִים גְּבוֹהִים עֲשָׂרָה טְפָחִים, אֵינָן נִמְדָּדִין עִמָּהּ. פָּחוֹת מִכָּאן, נִמְדָּדִין עִמָּהּ. וְאִם אָמַר לוֹ כְּבֵית כּוֹר עָפָר, אֲפִלּוּ הָיוּ שָׁם נְקָעִים עֲמֻקִּים יוֹתֵר מֵעֲשָׂרָה טְפָחִים אוֹ סְלָעִים גְּבוֹהִין יוֹתֵר מֵעֲשָׂרָה טְפָחִים, הֲרֵי אֵלּוּ נִמְדָּדִין עִמָּהּ:
If one says to his neighbor: "I am selling you a beth-kor of soil, if there were clefts ten handbreadths deep, or rocks ten handbreadths high, [(this, when they are four by four handbreadths wide, in which instance, they are "distinctive" places)], they are not measured together with it [and he must give him a complete beth-kor of level earth. For one does not wish to spend money on one place and have it look like two or three places. A beth-kor is 75,000 cubits. For the sanctuary courtyard was two sa'ah, and it was a hundred by fifty cubits; and a kor is thirty sa'ah. ("soil":) fit for sowing. But if he said: "beth-kor," unqualified, or "a beth-kor of ground," even if it were all rocky, the sale stands. For he could have wanted it for building a house or spreading out fruit.] And if he said to him: "as a beth-kor of soil," [connoting, as it is, whether rocky ground or (arable) soil], even if there were clefts deeper than ten handbreadths or rocks higher than ten handbreadths, they are measured with it.
Bartenura on Mishnah Bava Batra
English Explanation of Mishnah Bava Batra
But if they were less than this they are included.
If he said to him, “About a kor’s space of soil”, even if it contained crevices deeper than ten handbreadths or rocks higher than ten handbreadths, they are included in the measurement.
The seventh chapter of Bava Batra deals with errors in the measurement of fields discovered after they were sold. The question asked is must the buyer return the error to the seller if the seller gave more than the stated amount and vice versa, may the buyer demand that the seller give more land if the land was less than the stated amount.
According to our mishnah if a person promises to sell exactly a kor’s space of soil (about 20,000 square meters) then any crevices which are lower than ten handbreadths or rocks higher than ten handbreadth’s are not counted as part of the field. Since they cannot be used for planting, they do not contribute to the measure of a kor’s space of soil. However, if he sold him “about a kor’s space of soil” these rocks and crevices are included. Since he didn’t say that he was selling precisely a kor’s space of soil the measurements do not have to be precise.