Occurrence of Attributes in Original Text

The text related to the cultural heritage 'Messel Pit Fossil Site' has mentioned 'Volcanic' in the following places:
Occurrence Sentence Text Source
Contents 1 History 2 Depositional characteristics 3 Volcanic gas releases 4 Fossils 4.1 Mammals 4.2 Birds 4.3 Reptiles 4.4 Fish 4.5 Insects 4.6 Plants 5 Access 6 See also 7 References 8 Further reading 9 External links
Volcanic gas releases[edit]
hypothesize[example needed] that events much like the 1986 volcanic gas releases at Lake Nyos, Cameroon, could account for the large deposition of non-aquatic species (Franzen & Koster, 1994).
As they sank into deeper water, they were overcome by the release of toxic volcanic gas.