Why have archaeologists paused on exploring the burial site?

hey had been digging for days, shaded from the Greek sun by a square of green tarpaulin slung between olive trees. The archaeologists used picks to break the cream-colored clay, baked as hard as rock, until what began as a cluster of stones just visible in the dirt became four walls in a neat rectangle, sinking down into the earth. Little more than the occasional animal bone, however, came from the soil itself. On the morning of May 28, 2015, the sun gave way to an unseasonable drizzle. The pair digging that day, Flint Dibble and Alison Fields, waited for the rain to clear, then stepped down into their meter-deep hole and got to work. Dibble looked at Fields.

Explanation:

it is the boston port act