Dropstone

At the coast, fragments of glacier detach and float away as icebergs, which are often transported (ice rafted) many miles into the ocean, where they melt and deposit their load.

[1] Dropstones originating in this fashion are relatively rare in the geological record as most will land on high ground, which has a poor preservation potential as it is in an erosive environment.

However, a large blast may spread bombs far enough for them to end up in a marine setting of fine enough sediment for them to be recognized, or may land in or be buried by pyroclastic flows and surges.

[2] Boulders the size of a human have been found in relatively recent finely laminated sediments near Jamaica,[3] which has been a warm tropical island entirely devoid of glaciers since it came into existence.

Vertebrates, including ancient dinosaurs, may also act as dropstone agents by ingesting gastroliths and depositing them on land or within standing bodies of water by regurgitation or when the organism dies.

A number of meteorites have been found in Sweden's Thorsberg quarry, where they sank to the bottom of a shallow sea and were entombed in limestone 470 million years ago.

A dropstone of quartzite in layered rhythmite at Itu, Brazil
Glacial dropstone from Permian rocks in eastern Australia
Examples of gastrolith dropstones from the Tropic Shale ( Cretaceous ) of Utah