I have a vague theory for frogs and toads alledgedly found alive inside wood.
Wood: A frog or toad finds its way into a hollow in a tree where a branch has broken off below the surface of the trunk. The tree has grown a new
branch which has partially obscured the hole when the frog/toad enters.
The frog/toad has entered during the last days of Autumn (fall) so its getting cold. It goes into winter dormacy and remains in the hole and during
the fllowing mnths of winter the tree continues growing its branch, thus sealing the hole.
At this point there may still remain small holes or gaps allowing air exchange and moisture inside the hole. Before the end of winter the frog/toad
awakes and finds itself trapped, having no food it naturally returns to a state of dormacy.
There is a species of frog which lives in cool climate (not sure where, you could google it) When winter approaches it goes into dormacy, generating
chemicals that it allow it to be frozen solid, protecting only the vitals, heart etc , its actually frozen, yet its cells dont rupture. As the weather
warms, the frog thaws out and its organs speed up the metabolism and it hops away! Amazing!
So my idea is that our trapped frog having returned to dormacy, eventually goes deeper and deeper by some similar process that allows indefinate
preservation of tissues. perhaps it has moisture seeping into its hole containing nutrients leached from the bark etc allowing it minimal nourishment,
absorbed by the skin , perhaps some other unknown allows for oxygen exchange from the water seeping into into its hole, also absorbed by the skin?
So eventually, the tree is cut, the wood split and our frog, exposed to the air. The change in temperature or extra oxygen levels outside its woody
tomb, trigger a reverse of the process and after a while our frog begins to move again.
Truth is often stranger than fiction. As for rocks, perhaps its clay thats become petrified or petrified wood, same scenario?