2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I3I 



late, of most of the faunas. The situation in Florida is not so clear. 

 Bone beds at Melbourne and Vero overlie the Anastasia formation, 

 a marine Pleistocene deposit, and therefore are considered late Pleisto- 

 cene. Apparently a newer find at Haile in Alachua County may be 

 from a similar level. The Seminole Field in Pinellas County also ap- 

 pears to overlie the beds of the west coast of Florida that are con- 

 sidered equivalent to the Anastasia, if not exactly the same formation. 

 However, Pliocene exposures are near at hand so that the sequence, 

 from present knowledge, is not clear-cut as it is at Melbourne. In- 

 formation relative to the localities at Bradenton, Sarasota, and on the 

 Itchtucknce River is far from definite, and other deposits found in 

 caverns, while evidently Pleistocene, are still more uncertain as to 

 actual relationship within that period. Collecting continues actively in 

 the Florida Pleistocene, and presently there should be accumulated 

 sufficient data on the avifauna to permit a reasonable correlation. In 

 the meantime it has seemed better to list all the Florida records as 

 Pleistocene without attempt to indicate the level. To list Melbourne 

 and Vero alone, for example, as late Pleistocene might be misleading. 



Recent investigations of Dr. Joseph T. Gregory (Condor, 1952, 

 pp. 73-88) have changed measurably the time-honored concept in 

 which the species of Ichthyornis have been associated with the 

 Hcsperornis group in a superorder (Odontognathae) of the Neorni- 

 thes, characterized by the possession of teeth. The skull of Ichthyor- 

 nis always has presented an anomaly in that the teeth were in sockets 

 instead of in grooves as in Hcsperornis. Further, the mandible, or 

 lower jaw, was unduly large in comparison with the rest of the skull 

 and the body skeleton. Dr. Gregory has shown that the jaws attributed 

 to Ichthyornis in reality are reptilian and are those of a small 

 mosasaur. 



These conclusions destroy the main reasons for the association of 

 Ichthyornis and Hcsperornis in one superorder, though still leaving 

 Ichthyornis apart from birds known from later periods to the present, 

 in the biconcave vertebrae. In preliminary consideration it seemed 

 that it might be desirable in the classification to cancel the category 

 of superorders, but on further consideration it appears useful to 

 emphasize the considerable and definite differences that separate 

 Hcsperornis, Ichthyornis, and the penguins from each other and from 

 other groups of birds. This may be accomplished through a new 

 superorder Ichthyornithes for the order Ichthyornithiformes, leaving 

 Hcsperornis and those others placed near it in the Odontognathae. 

 This will serve as stated above to call attention to the existing peculi- 

 arities of these groups and will give a balanced treatment. 



