Name: Modocia
sp. (brevispina?); Agnostida (sp indet)
Class
Trilobita, Order:
Ptychopariida, Family Marjumiidae & Order
Agnostida
Geological
Age: Middle Cambrian
Size: Modocia:
17 mm long and 12 mm wide, 7 mm long and 5 mm wide Agnostids: 2-8 mm long
on a 200 mm by 118 mm matrix
Fossil
Locality: House Range, Marjum Formation, Millard County, Utah
 Description:
Coming from the Cambrian Marjum Formation deposits of Millard County,
Utah this is a fine association plaque of two trilobites of quite
disparate morphology.  The
larger trilobite is an example of the genus Modocia. A second smaller
example missing the librigenae is also present. There are also over
THIRTY, 2- 8 mm trilobites of order Agnostida. Members of the Agnostida
are often found in mass mortality in the various House Range Cambrian
strata, and often in association with trilobites of other orders,
particularly the Ptychopariids.
Most agnostids are blind trilobites, and have a pygidium essentially
equal in size to the cephalon (ispopygous), making it hard to tell
which end was which.
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