O. Meyer—Species in the Southern Old-tertiary. 457 
Arr. LIX—The Genealogy and the Age of the species in the 
Southern Old-tertiary; by Orro Meyer, Pu.D. 
Havine for some time been engaged in the study of the Old- 
tertiary formation of the Southern States, especially of Alabama 
and Mississippi I have reached the following results: 
1. This formation contains so many forms that have not 
hitherto been made known, that the existing lists, their other 
faults not considered, can be said to give only a poor picture of 
this fauna. 
2. For the three main localities, Vicksburg, Jackson and 
Claiborne, which are succeeding beds, a genealogy (see the table 
beyond) can be made out for many species) They can be 
traced through two beds or all three of them, either remaining 
unaltered, or varying somewhat, or varying in such a degree, 
that different specific names must be used. In other words: 
many described and undescribed species are most probably 
connected by descent. 
8. Since the discovery of these beds it has been generally 
accepted, that the “ Claibornian” is the oldest and that their 
succession is as follows: Claiborne (Middle Eocene), Jackson 
(Upper Eocene), Vicksburg (Oligocene); the existing maps are 
colored accordingly. This has been done without sufficient 
reasons and it is even very probable that the succession is just 
the contrary—Vicksburg the oldest and Claiborne the most 
recent formation. 
As for the new species I hope to be able to describe them 
soon. I am obliged to nameand describe a part of them in the 
following pages without figures. But most of them are defined, 
though briefly, yet exactly, by giving the differences from 
allied known species. I think that a paleontologist collecting 
at the same locality will be able to recognize them, and this 
is more than can be said for many species described and fig- 
ured from this Tertiary. 
: Part I. 
The Genealogical Relations of the Species. 
If we have three formations, one above the other, not sepa- 
rated by a geological gap or by long geological times, but ap- 
parently deposited during a gradual rising of the coast, we may 
expect the following. Many of the species will remain un- 
changed or vary to some extent, others will vary very much. 
If variations of a species disagree more and more they may 
Am, Jour. Sct.—Turep Series, Vou. XXIX. No. 174.—Junz, 1885. 
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