At https://phys.org/news/2025-02-underwater-fossil-bed-collectors-rare.html … hundreds of mammal fossils have been recovered from the Steinhatches River in Florida, dating back to around half a million years ago. It is postulated that various animals, such as horses, sloths, and armadilloes, fell into a sink hole and were unable to get out. They quickly died and we are told they were then fossilisied – without anything eating them. The fossils are described as near perfect which would suggest quick burial – and then fossilisation. Sink hole or not the fossil collectors clearly found them on the bed of the river – so the evidence for a sink hole needs to be addressed, or assessed. Palaeontologists have dated the fossils to the Irvingtonian period, which occurred during the Pleistocene ice age era. For the full story you need to access the journal link at https://doi.org/10.3390/fossils2040014 …
See also https://www.livescience.com/planet-earth/geology/worlds-biggest-underground-thermal-lake-discovered-in-albania-at-bottom-of-330-foot-abyss … Czech scientists have found a large underground thermal lake on the border between Albania and Greece. The lake lies at the bottom of an abyss 330 feet deep – and how deep the lake, itself, would increase the cavity even further, one might suspect. They also stumbled on an extensive system of caves – some with thermal springs. Lots more investigating to go.