silurian

adj

1. Of a geologic period within the Paleozoic era; comprises the Llandovery, Wenlock, Ludlow and Pridoli epochs from about 439 to 409 million years ago.

   “In some places, however, quartz reefs, payably auriferous while in Silurian rock, have been followed down to subjacent granite, and have there been found to thin out and become unprofitable […]”

2. Of or related to the Silures, a pre-Roman British tribe.

noun

1. A member of the Silures, an ancient tribe of Britannia.

name

1. The Silurian period.