Geologists have identified fossils of these cysts only as far back as the Silurian period
, roughly 420 million years ago.
is would date back to the Silurian period
, so is probably around 420 million-years-old.
lived in the ocean about 425 million years ago during the Silurian period
, a time when the hot new kind of animal on Earth was the newly evolved bony fish and when the only major life forms on land were moss-like plants.
These formations are remnants of a vast sea that covered what is today's western and central New York during the Silurian period
, some 400 million years ago.
With support from the National Geographic Society's Committee for Research and Exploration, Rohr and his colleague Robert Blodgett have found striking similarities between the Alaskan fossil shells and shells from Europe and Russia that date back to the same time, the Paleozoic era's Silurian period
, between 417 million and 443 million years ago.
It is not uncommon to uncover it among the thinly bedded banded horizons of the Eramosa Formation (from the Silurian period
, 425 mil lion years old) in quarries around Wiarton, although it may be overlooked in favour of more rare fossils that "look like something.
9 Nature, a team of British and Russian scientists describes the petrified remnants of a vent community that thrived during Earth's Silurian period
, which ran from 438 million to 410 million years ago.