Man this is like something out of Sunless Skies, hell yeah.

Its from an Arthur Conan Doyle story

Damn, didn't know he did this kinda stuff, is it good?

It's pretty good, it's about a journal found near a crashed plane with no trace of the pilot, and the journal reveals that he'd been investigating several other mysterious deaths and disappearances of pilots. He discovers that above the then-explored limit of 30.000 feet (the story was written in 1911), there's an entire ecosystem of strange, alien beings, just like the bottom of the ocean has. And it has some deadly predators.

okay yeah that fuckin rules I'm gonna check it ou-OH wait right

Conan Doyle also did "The Lost World" this would totally be his thing.