from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. An isolated fragment of rock found within a sedimentary rock (that had fallen, rather than being carried along)
from The Century Dictionary and Cyclopedia
- n. A stalactitic variety of calcite. See stalactite.
First, they have a variety of data flags, including flags for turbidity, earthquake, drainage event, and dropstone, indicating that the particular data point is not to be used.
The dropstone group gathered a 150 graduation speeches together and attempted to code and extract "meta-advice" by combining the insights together.
PS I mapped a few thousand sq miles of late Precambrian in the Richtersveld, just inside South Africa years ago, which was older than the Nama and included the Numees tillite in which I found a stromatolite in associated dolomite, and also a dropstone and varves.