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Acaste (genus)
Encyclopedia
Acaste is a genus of extinct trilobite
of the order Phacopida
which lived throughout the Silurian
period. They are characterized by a convex dorsal surface, an absence of spines, a shortening of the head-shield and a general rounding off of all angles . Species include Acaste downingiae (Wenlock Series
) and Acaste birminghamensis, discovered in the Red Mountain Expressway Cut
.
Trilobite
Trilobites are a well-known fossil group of extinct marine arthropods that form the class Trilobita. The first appearance of trilobites in the fossil record defines the base of the Atdabanian stage of the Early Cambrian period , and they flourished throughout the lower Paleozoic era before...
of the order Phacopida
Phacopida
Phacopida is an order of trilobite that lived from the Ordovician to the Devonian. It is made up of a morphologically diverse group of related suborders....
which lived throughout the Silurian
Silurian
The Silurian is a geologic period and system that extends from the end of the Ordovician Period, about 443.7 ± 1.5 Mya , to the beginning of the Devonian Period, about 416.0 ± 2.8 Mya . As with other geologic periods, the rock beds that define the period's start and end are well identified, but the...
period. They are characterized by a convex dorsal surface, an absence of spines, a shortening of the head-shield and a general rounding off of all angles . Species include Acaste downingiae (Wenlock Series
Wenlock Series lagerstätte
The Silurian lagerstätte preserved in the limestone Wenlock Series of Herefordshire, England, offers paleontologists a rare snapshot of a moment in time, about 420 Mya. In the formation, layers of fine-grained volcanic ash punctuate a sequence of carbonate muds that were accumulating in a marine...
) and Acaste birminghamensis, discovered in the Red Mountain Expressway Cut
Red Mountain Expressway Cut
The Red Mountain Expressway Cut also known as the Red Mountain Geological Cut is a section of Red Mountain that was blasted and removed in the 1960s to allow the Red Mountain Expressway to enter downtown Birmingham, Alabama. This highway linked Birmingham with its southern suburbs of Homewood,...
.