Vol. 4 of this catalogue updates, but does not replace, previous entries; no new Grand Canyon Type Fossils are recorded herein. For each entry, the Grand Canyon Type Fossil number appears against the right margin. Each entry is also crossreferenced to Vols. 1 and 2 (Spamer, 1983, 1984, Geol. Soc. merica Microform Pub. 13, 14); no entry herein refers to entries that appeared in Vol. 3 (Spamer, 1988, Geol. Soc. America Microform Pub. 17). The systematic index that appeared in Vol. 3 is still current.