Serapeum of Saqqara (Apis catacombs)

Twenty-four stone boxes, each 60 tonnes or more, sunk into chambers below the gallery floors

Greater Vaults begun Psamtik I (664-610 BCE), extended to Ptolemaic era; earlier tombs…

Mariette found winches and roller traces, and proposed lowering the boxes on sand. Does that method explain the tight chambers, or only part of the job?