If he found three corpses lying parallel to each other, then if there is between them, i.e., the outer two corpses, a distance of four to eight cubits, then this is presumed to be a graveyard and the corpses may not be removed, and he must examine from that spot outward twenty cubits to discover whether there are other corpses buried there. If he finds even one corpse up to the distance of twenty cubits, he must continue to examine from the place he finds that corpse outward another twenty cubits. He continues to search for additional corpses, even if only one corpse was found within the twenty cubits, as there is a basis for anticipating the matter; it is probable that he has stumbled upon an ancient cemetery. He is not permitted to relocate the corpses, despite that fact that if he had found the single corpse by itself at first, without being aware of the gravesite, he would have been permitted to remove it and its surrounding earth.

The Gemara analyzes that mishna. The Master said: If there is between them a distance of four to eight cubits, then it is presumed to be a graveyard. The reason is that corpses buried in this manner are indicative of the standard layout of a burial chamber. The fact that this is said only when the distance between the corpses is between four and eight cubits assumes that the size of a burial chamber is four cubits by eight cubits. Based on this, the Gemara asks: Whose opinion is this? If it is the opinion of the Rabbis in the mishna above (100b), didn’t they say that the size of a burial chamber is four cubits by six cubits? If it is the opinion of Rabbi Shimon, didn’t he say that a burial cave is six cubits by eight cubits?

The Gemara answers: Actually this mishna is in accordance with the opinion of Rabbi Shimon, and it is in accordance with another version of Rabbi Shimon’s opinion, which is cited by this tanna, as it is taught in a baraita: If one found three corpses lying in close succession, and there is not a distance of four cubits to eight cubits between them, i.e., they are lying closer together, they have the halakha of the requirement to move their surrounding earth in which they are buried. But they are not considered to be part of a graveyard, since permanent graves are not placed so closely together. Perforce, their corpses were originally buried there on a temporary basis, but then they were never reinterred. Rabbi Shimon ben Yehuda says in the name of Rabbi Shimon: The corpses in the middle are viewed as if they are not there, i.e., as if they were buried there incidentally, and the other corpses thereby combine to form a graveyard in which corpses are found with a distance of four cubits to eight cubits between them.

The Gemara asks: In accordance with which opinion did you interpret the mishna? If it is in accordance with the opinion of Rabbi Shimon, then say the latter clause of that mishna: If he finds an area of graves, he must examine from there outward twenty cubits to discover whether there are other corpses buried there. Since the burial formation is indicative of burial within a burial chamber of a catacomb, he should continue to investigate the whole area that would be occupied by a catacomb. The Gemara asks: Whose opinion is this? If it is the opinion of Rabbi Shimon, the distance one should be required to examine would be twenty-two cubits, which is the total length of a catacomb, i.e., two chambers of eight cubits with a courtyard of six cubits between them. If it is the opinion of the Rabbis, the distance one should be required to examine would be eighteen cubits, as each catacomb consists of two chambers of six cubits long with a chamber of six cubits between them.

The Gemara answers: Actually, the mishna is in accordance with the opinion of the Rabbis, and it is necessary to examine twenty cubits in a case where he examined along the diagonal of the catacomb, which is longer than its length.

The Gemara asks: But since he examined this chamber along the diagonal, this second chamber on the other side of the courtyard should also be examined along the diagonal. If so, that would be twenty-two cubits. The Gemara answers: We say he should examine one chamber along the diagonal, but we do not say he should examine two chambers along the diagonal.