The place lots of paleontology aficionados call Extinction Canyon, situated within Nevada's Great Basin Desert, is especially noted for producing locally common whole and mostly complete early Cambrian trilobites.
Other extinct organisms often found in an excellent state of preservation in the general vicinity of the canyon's corridor include: graptolites (usually considered an early hemichordate); hyolithids (a lophophorate tangentially related to Brachiopoda, Bryozoa, and possibly phoronid annelids); Caryocaris crustaceans; a tabulate coral; archaeocyathids (early calcareous sponge); salterella (small ice cream cone-shaped fossil assigned to its own unique phylum called Agmata--it never survived the early Cambrian); Lidaconus (a diminutive tusk-shaped shell of unestablished zoological affinity that went belly-up near the conclusion of the early Cambrian); and Girvanella algal nodules precipitated by a species of photosynthesizing cyanobacteria.
Needless to report, Extinction Canyon is a genuine ne plus ultra paleontological district, indeed.