Llandovery
Geologic period
In the geological timescale, the Llandovery Epoch occurred at the beginning of the Silurian Period. The Llandoverian Epoch follows the massive Ordovician-Silurian extinction events, which led to a large decrease in biodiversity and an opening up... Wikipedia
Period: Silurian
Occurred: 443.8 (+/- 1.5) million years ago - 433.4 (+/- 0.8) million years ago
Ages: Rhuddanian, Aeronian, and Telychian
Lower boundary definition: FAD of the Graptolite Akidograptus ascensus
Lower boundary GSSP: Dob's Linn, Moffat, UK; 55°26′24″N 3°16′12″W / 55.4400°N 3.2700°W
Lower GSSP ratified: 1984
Upper boundary definition candidates: A conodont boundary (Ireviken datum 2) which is close to the murchisoni graptolite biozone