748 A. C. PEALE 
River beds, only nine are actually found in the Judith basin of 
Montana. Four of these are types and of these, only two are con- 
fined to the Judith beds. The other seven are common to both the 
Judith and Lance formations which, in view of what Dr. Hay has 
written, is good proof of their identity in age. 
The most abundant and conspicuous reptiles in both the Judith 
River and the Lance formations are the dinosaurs, and practically 
half of those listed by Hatcher are common to both formations. 
Writing of these dinosaurs Dr. Hay says.’ 
Five families of these, belonging to four super-families and to two suborders, 
are represented in the Judith River epoch, and each of these families reappears 
in the Lance Creek epoch. Furthermore, many of the genera are common to 
the two formations and it is believed that the same is true of a considerable 
number of species. 
Hatcher in his summary in the consideration of the dinosaurs? 
says that ‘‘they of all the vertebrates of these beds [Judith River] 
afford the best basis for a comparison of the fauna of these deposits 
with that of the Laramie [Lance] above (?) and the Jurassic below.” 
He says the great group of Sauropoda which formed a conspicuous 
feature at the close of the Jurassic and the beginning of the Cre- 
taceous is entirely wanting, and that the Stegosauria, which formed 
a striking feature among the Jurassic dinosaurs, have almost or 
quite disappeared, being entirely replaced by the quadrupedal 
Ceratopsidae and the bipedal ‘Trachidontidae. ‘“‘No unmis- 
takable representative of the Stegosauria is certainly known from 
the Judith River beds. Palaeoscincus, referred to this suborder 
chiefly on the evidence of teeth alone, may or may not pertain to 
the Stegosauria, while Siereocephalus appears to have been founded 
on material belonging in part to the Crocodilia and in part to the 
Dinosauria.”’ On the following page Hatcher states that these 
Dinosauria are not distinguishable from remains from the Laramie 
[Lance] at present referred to the Ceratopsia. Whether or not 
Palaeoscincus costatus, described from the Judith River badlands 
by Leidy in 1856, is represented in the Lance formation by numer- 
ous teeth’ cannot be positively stated. The genus is represented 
OD Cit De23e 
2 Bull. U.S. Geol. Surv., No. 257, pp. 101-3. 
3 Hatcher, op. cit., pp. 83, 88; Hay, op. cit., p. 23. 
