in the Southern Old-terUary. 425 



I select here three cases, where the determinations of Hilgard 

 are imaginary. The first includes those based upon Zeuglodon. 

 Wherever he finds Zeuglodon or hears tha.t the bones of this 

 animal have been found, he maps the locality as Jacksonian. 

 He thus uses Zeuglodon practically as a Jacksonian a fossil, 

 It is not necessary to repeat here what is said about a fossils in 

 general, but we may be somewhat surprised to find that, accord- 

 ing to our definition, Zeuglodon is even not a d fossil, that is, 

 it is not found among the marine shells of Jackson (see list of 

 Jackson fossils, I, p. 132). What are the facts, then, cited in 

 I, where Zeuglodon is found with other fossils ? 



1. From observations at Moody's Branch and in the McNutt 

 Hills, Hilgard deduces that Zeuglodon bones have been found 

 above the Jackson fossils, above but separated only by a few feet 

 (pp. 130, 131). 



2. Zeuglodon found with Cypraea fenestralis and Comes tor- 

 tilis "and a very large Pyrula not seen elsewhere" (p. 134). 

 The first species is a Jacksonian 8 fossil, but Conus tortilis (= Co- 

 nns sauridens) extends from Yicksburg to Claiborne (see part I of 

 this essay, p. 466). 



3. Zeuglodon found with Ostrea, Pecten ?iuperus, Scutella. 

 Pecten nuperus (=P. Deshaysi Lea) is either a /? or not " recog- 

 nized " y fossil. 



4. Zeuglodon associated in prairies with " an oyster somewhat 

 resembling Gryphcea convexa of the Cretaceous, the vertebras and 

 teeth of fish and a branching coral {Eschara sp.), (p. 128.) 



On these facts, so far as I am aware, Hilgard bases the use of 

 Zeuglodon as a Jacksonian a fossd in I. In a later article 

 (this Journal, 1866, p. 68), he cites Zeuglodon with three Jack- 

 sonian 8 fossils. I collected and have in my possession parts 

 of the skull, etc. of Zeuglodon associated with the oyster and 

 coral just mentioned, and Pecten Deshaysi Lea, between Barnett 

 and Pachuta, Clarke Co., Miss., near the New Orleans E. R.,* I 

 have seen a large vertebra of Zeuglodon in a little street in 

 Enterprise, Miss., that is in a locality which I consider as Clai- 

 bornian ; I do not know, however, whether it was found there, 

 or brought from a distance. I have had sent me from Claiborne 

 the vertebra of a large marine mammal, which I have presented 

 to the Yale College Museum; I do not know, however, where it 

 was found. The whole literature about Zeuglodon cannot be 

 cited here, but altogether I must say that we do not know when 

 and how long Zeuglodon was living in the waters of the South- 



* The greatest part of the same specimen had been collected, before I came to 

 this locality. I saw it afterwards in the exhibition in New Orleans (1884), ex- 

 hibited by the State of Mississippi. 



Am. Jour. Sci.— Third Series, Vol. XXX, No. 180.— Dec, 1885. 

 27 



