The earliest history of land-living vertebrates, from 370-320 million years before present, is represented by a very few fossils from a handful of localities. Most of these fossils are poorly preserved and incomplete, which makes it difficult for paleontologists to interpret the early history of terrestrial vertebrates. Much has been learned from study of the currently-available fossils, and more can still be learned from the few available examples. However, further progress in understanding the earliest history of land-living vertebrates will come primarily from the discovery of new fossils. In 1985, a new locality containing numerous fossils of early land vertebrates was discovered in southeastern Iowa near the town of Delta. The Delta site has been dated by geologists at about 340 million years old, which makes it the oldest early-land-animal locality in the United States, and one of the oldest in the world. Over a periods of three years, more than 600 specimens including about 50 partial skeletons, some nearly complete, were collected; most of this collection is stored in the Field Museum of Natural History, and some at the University of Iowa. The fossils are well-preserved and the collection represents the largest number of good specimens of any early-land-vertebrate locality. At least three new species are present, each very primitive. These three species represent an increase of about 20% in the known number of such early land vertebrates. The Delta fossils thus comprise one of the most significant paleontological discoveries in decades. Field Museum fossil preparators have already spent over 3,000 person-hours on Delta specimens. Support for this research project will fund a further 700 hours of technical help. The majority of this effort (560 hours) will be focused on preparing additional key specimens of the most abundant species in the delta collection for scientific study. The remainder (140 hours) will be used to produce scientific illustrations of this species for publication.
