A very high excess of oxygen, methane, and nitrous oxides would certainly be suggestive of life.
The archaeologists found no pottery, ornaments or paved surfaces which might be suggestive of formal graves or burial rituals.
The natural images in the poem are meant to be suggestive of realities beyond themselves.
It might be suggestive of overall construction integrity, but how do you know what evil might lie under that handle or at the joint you really can't see?