stratusfear

Those are pieces of an onyx chess set. I used to have that exact set. Here’s an example from ebay: https://www.ebay.com/itm/276268677793?itmmeta=01HQGDMT5HNWBF8YNWTDN1Q1D5

This is incorrect. Very little of the soil that existed before the Cenozoic has been preserved. There was soil. The wikipedia article you linked states this.

That looks like maybe a bottle fly. Googling indicates the adults last 50 to 60 days¹.

¹ https://www.researchgate.net/publication/344275278_Longevity_of_Adult_Lucilia_eximia_WiedemannDiptera_Calliphoridae_Under_Standard_Conditions

Tim Traveller is one of my favorite channels.