204 The American Naturalist. (March, 
THE TITANOTHERIUM BEDS. 
By J. B. HATCHER. 
In 1857 Meek and Hayden gave the name Titanotherium bed 
to the lowest member of the fresh water, Miocene, lake depos- 
its of the White river, Bad Lands of Dakota and Nebraska.’ 
They named these beds from the genus Titanotherium, estab- 
lished by Leidy in 1852? This genus embraces the largest, 
most abundant, and most characteristic vertebrate fossils found 
in these beds. In 1870 Professor Marsh discovered, in north- 
eastern Colorado, an exposure of these beds, farther south than 
they had then been reported? He then referred them to “The | 
true Titanotherium beds.” In 1877 Professor Marsh proposed 
the name Brontotherium beds for this same series of strata, from — 
his proposed genus Brontotherium.' Since there can be no doubt 
that the Titanotheriwm bed M. and H., and the Brontotherium beds 
Marsh, are identical, and since the former has a priority of 3 
at least twenty years, it should be retained.” In this paper — 
the plural will be used, as expressing more nearly the true — 
nature of the deposits. 
GEOGRAPHICAL DISTRIBUTION OF THE TITANOTHERIUM BEDS. © 
The Titanotherium beds are known to have a surface expo 
sure in various portions of the western interior plains region. 
That exposure from which they were first named and descri n 
and from which Hayden first made and published a section of 
them in 1863, is of far greater extent than any other. +” 
Titanotherium beds of this exposure are known to occupy è 
1Proc. Phila. Acad. Nat. Sci., 1857, p. 120. 
2Ancient Fauna of Nebr., Leidy, 1852, p. 72. 
*Am. Jour. Sci., Sept., 1870, p. 292. 
1Am. Jour. Sci., 3d series, Vol. xiv, p. 354. 
‘Titanotherium, Leidy, 1852, is antedated by Menodus Pomel, 1849 5 
Menodus is essentially preoccupied by Menodon von Meyer, 1838. 
Proc. Am. Phil. Soc., 1863, Vol. xii, p. 31. 
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