The third locality, and that yielding most of the recently obtained specimens, is the Inversand Company marl pit, located near Sewell, Gloucester County. In accordance with the wishes of the Inversand Company, the precise locality of this pit will not be disclosed, although this information is preserved in records sufficient in number and distribution to assure that it will not be lost. The Inversand specimens came from the main fossiliferous layer within the basal portion of the Hornerstown Formation ([Figure 3]). This layer is of late Maastrichtian age (latest Cretaceous), on the basis of invertebrate fossils, including three genera of ammonites, and a substantial vertebrate fauna, including mosasaurs (see Appendix). It is probable that the upper part of the Hornerstown Formation within the pit is of Paleocene age, as it is known to be elsewhere, but most paleontologists believe the basal portion to be Cretaceous in age (Gaffney, 1975; Koch and Olsson, 1977). One avian specimen is from an unknown level in the pit.
Figure 3.—Stratigraphic diagram of the Inversand Company marl pit at Sewell, Gloucester County, New Jersey.
Order Charadriiformes
"Form Family" Graculavidae Fürbringer, 1888
Type Genus.—Graculavus Marsh, 1872.
Included Genera.—Graculavus Marsh, 1872; Telmatornis Marsh, 1870; Anatalavis, new genus; Laornis Marsh, 1870; Palaeotringa Marsh, 1870; and an additional unnamed genus.
Remarks.—Most of the birds from the New Jersey deposits belong with what Olson (1985) has termed the "transitional Charadriiformes," a group that seemingly tends to connect the Gruiformes and the more typical Charadriiformes. The only living family in this group that has traditionally been considered charadriiform is the Burhinidae, the thick-knees or stone curlews. Other apparent descendants include ibises (Plataleidae) and the ducks and geese of the order Anseriformes. The latter are linked with the "transitional Charadriiformes" through the Paleocene and Eocene genus Presbyornis, which is known from abundant material from widely scattered areas of the world (Olson and Feduccia, 1980b; Olson, 1985). Presbyornis combines a long-legged shorebird-like body with the head of a duck. The fragmentary Cretaceous fossils from New Jersey, all of which are postcranial, usually show more similarity to Presbyornis than to any modern group of birds except the Burhinidae. Therefore, our comparisons have been made chiefly with these two groups.
With the fragmentary material at hand it is difficult, well nigh impossible, to make hard and fast taxonomic judgments concerning the number of species, genera, or families represented. Birds with very similar wing or leg elements could have had completely different feeding adaptations and could represent ancestral forms leading to different modern groups not considered to be closely related. For example, without the skull, Presbyornis could not be determined as having anything to do with the Anseriformes (Olson and Feduccia, 1980b: 12-13).
Late Cretaceous fossil birds of modern aspect have been described in a variety of genera, most of which have been used as the basis for family-group names. Taxa from New Jersey that appear to belong with the "transitional Charadriiformes" for which family-group names are available include: Graculavinae Fürbringer, 1888; Palaeotringinae Wetmore, 1940; Telmatornithidae Cracraft, 1972; and Laornithidae Cracraft, 1973.