The removal from one grave to another
A. One who gathers or guards the bones is exempt from reading Shema, prayer, and all the precepts commanded in the Torah, and if he desires to be rigorous with himself, he must not do so, for the honor of the dead. R. Johanan b. Nuri, however, said: He should step outside a distance of four ells and read. Ben Azai said: If they were with him in a boat he should remove them to another place and read. R. Itzhak said: Only from the bones of relatives he is exempt; from strangers, however, he is not. R. Simeon said: He is exempt only on week-days, but not on Sabbath. R. Nathan, however, said: He is exempt only when the bundle (of the bones) is on his shoulders, because the duty of guarding it is on him, but not of prayer.
B. One who removes bones or the Scriptures from one place to another, must not place them in a wagon, a boat, nor on a beast under his seat: however, in order to preserve them from thieves or robbers, he may. B1
C. It is not allowed to pass through a cemetery with the phylacteries on, nor the Scriptures in the hand, as it is considered disrespectful to the dead. C1
D. One finding a corpse in a grave must not move it, unless he is certain that the place was only borrowed for him. One finding bones on marshy ground, must put them in a grave. Such is the decree of R. Aqiba. The sages, however, say: He must not move them. One who finds bones in a grotto or a cavity must not move them. A corpse or his bones must not be moved from one place to another, even if they are equal in esteem, much less if the other place is lower; he may, however, do so from a lower to a higher place. However, if he moves them to a place on his estate, he is allowed to do so, even if the former place is more esteemed. D1
Two corpses must not be buried in one grave, nor a corpse with bones, and vice versa. R. Jehudah, however, said: If they used to sleep together when alive, they may be buried together.
E. A building over a grave which was vacated, no benefit may be derived from it; if, however, it was excavated in a rock, and also the grave itself, when it was vacated a benefit may be derived from it; nevertheless, it must not be used for low purposes, such as a cow-house, straw-barn, etc. A grave which was dug for a person who was yet alive may be sold; but if for one who was already dead, it may not. The same is the case with monumental stones.
No benefit may be derived from a vacated coffin. If it is made of stone or clay, it must be broken, and if of wood--burned. Boards of the cemetery must not be moved from their place.
B. Corrected from Berachoth.
Sources: Sacred Texts