340 The American Geologist. J""^- ^^^^ 
writer has had the opportunity of describing a fine large 
species of the genus, Hadrianus majusculus. from the still 
older Wasatch beds. So far as he knows, nothing older of 
the family has been described. Dollo has reported a Tes- 
tudo from the Lower Eocene of Belgium, .but it appears not 
yet to have been described. Whether it is a true Testudo 
or a Hadrianus remains to be seen. The ancestry of the 
family evidently goes back into the Cretaceous, and its 
fatherland we know not. 
It may be instructive to consider what elements are 
conspicuously missing from the Bridger turtle fauna. There 
are no marine forms; no Thalassochelys, no Argillochelys, 
no I.ytoloma. A\'e must infer from this and other facts, 
that the basin was well shut off from the sea. There are 
likewise no Pleurodira. It is more surprising that there 
are no undoubted Chelydridse; for Anosteira may better be 
retained in a family of its own. Chelydra has the marks 
of an ancient form, and we might suppose that the condi- 
tions furnished in the Bridger basin were eminently favor- 
able for its existence ; but Chelydra first appears in the Up- 
per Oligocene of Europe. It is not known that the genus 
appears in America before the Pleistocene, for Chelydra 
crassa Cope, of the Puerco, must be regarded as a derma- 
temyd, to be called Hoplochelys crassa. There are no Cin- 
osternidae. Among the Emydidae, there is no true Emys, 
v^ath hinged plastron : nor any Terrapene, box-tortoise, with 
a more perfectly hinged plastron. The emyds present prob- 
ably belong neither to Chrysemys nor to Clemmys, although 
■closely related to both. 
Professor Osborn (Ann. X. Y. Acad. Sci., xiii, 1900, pp. 
19, 46) synchronizes the Bridger beds with the Bartonian 
and the lower portion of the Ligurian. So far as the writer 
knows, the Barton has furnished no turtles. On the con- 
trary, the Ligurian. as represented in England and France, 
has yielded numerous turtles. These are mostly Triony- 
chidae. which have been described under the name Trionyx, 
but would be included by the writer under Amyda. There 
are also Emydidae. a supposed Anosteira, and a supposed 
dermatemyd, Trachyaspis hantonensis. There are no Plas- 
tomenidae, no Testudinidae, and no Amphichelydia. The 
