Page 386 - Introduction to Paleobiology and The Fossil Record

ECDYSOZOA: ARTHROPODS 373

pelagic fauna

illaenid–
cheirurid
association
nileid olenid
association association
graptolite
shales
Valhallfonna
(a) Formation
shelf illaenid–cheirurid–
faunas lichid association
“intermediate”
faunas
platform edge
(or tectonically Opsimasaphus–
elevated area Nankinolithus
within basin) association
typical lithofacies
carbonate
Novaspis–cyclopygid
calcareous Crugan Mudstone fauna association
argillaceous
Dwyfor Mudstone fauna
mudstone
(b)

graptolitic shales and
sandstone belt shelf limestones shale belt sparry algal limestones
turbidites
Proetus–Warburgella Dalmanites–Raphiophorus Radnoria–Cornuproetus
Acaste–Trimerus association Delops–Miraspis association
association association association
Acaste
Cornuproetus
Trimerus
Calymene Scutelluidae
P Proetus
Radnoria
W Warburgella
illaenimorphs
Harpidella illaenimorphs
Dalmanites
Raphiophorus
Decoroproetus Decoroproetus
Proromma
Delops and Struveria
nodulosa-type calymenids Miraspis

(c)
Figure 14.10 Trilobite communities: overview of (a) Early Ordovician (Arenig), (b) Late Ordovician
(Ashgill) and (c) Mid Silurian (Wenlock) trilobite associations in relation to water depth and
sedimentary facies. (a, from Fortey, R.A. 1975. Fossils and Strata 4; b, from Price, D. 1979. Geol. J.
16; c, from Thomas, A.T. 1979. Spec. Publ. Geol. Soc. Lond. 8.)