She wondered how deep it was. A blanket - no - more like a massive pile of fog meant she could barely see the sides, let alone the bottom. A gorge implies something deep; gargantuan, though.
Could a person survive a fall into there? Suddenly all she could feel were invisible hands, grabbing at her, pulling her forwards; she felt giddy and stepped back from the edge. A wide, but uninteresting moon shone through thick cloud. The cloud was thick like the fog. She wondered if the fog was thick enough to slow her fall; how thick would it have to be? Would she have a few moments' more time to contemplate her fate? And in the morning; would the fog slowly fall around her, bury her? Would they ever find her under the fog? Would anyone ever find her?
Sylvia sat on the cool stone; she began to laugh, to weep; she couldn't quite tell which.