Comment by rolph

sarcophagus looks to be 2 feet by 7 feet based on scale of objects in the image.

is 1.75 cubic feet of solid material reasonable?

the image displays distinct relief cracks of a drying wet slurry, the dark staining inside the coffin suggests high fluid mark was maybe 4inches, it may have knocked an urn over, before recedeing, and evaporating.

while not up on the finer points of such burial practice, it doesnt seem unreasonable that a consideral amount of flowers and other plant materials may be involved, there should be considerable pollen present, potassium and sodium salts of the decedent, adipocere, and perhaps diatoms dependent on the nature of the soil, and source of water percolating into the sarcophagus.

i believe considering it to be just mud, would be to overlook, a volume of pertinant discovery.