274 STUART WELLER 
bed beneath the limestone. In southeastern Missouri a one-foot bed 
of sandstone occurs at the base of the Kinderhook with numerous 
phosphatic nodules and some worn Ptyctodus teeth. In southwestern 
Missouri a thin formation at the base of the Kinderhook has been 
described by Shepard? as the Phelps sandstone, in which Ptyctodus 
teeth are abundant, and the same conditions obtain at Providence,’ 
in central Missouri. In all of these localities the same species, P/yc- 
todus calceolus N. and W., seems to be the usual form. Occupying, as 
these Ptyctodus beds do, a position immediately superjacent to a more 
or less profound unconformity, it is not likely that it is strictly contem- 
poraneous in all of these localities, but that they are all associated 
with one general geologic movement, and are contemporaneous within 
comparatively narrow limits, is quite certain. The presence of the 
remains of this fish fauna, in both the southern and northern Kinder- 
hook provinces, while the invertebrate faunas are so distinct, is doubt- 
less due to the fact of the greater mobility of the fishes, and their 
greater powers of adaptation to certain changing conditions. 
Besides these fish remains, the most common fossil in the Sweetland 
Creek beds is a crustacean belonging to the genus S pathiocaris, which 
also occurs in the Upper Devonian black shale in southern Indiana 
and Illinois, and in a basal Kinderhook shale in southwestern Mis- 
souri. This crustacean, like some of the Lingulas, seems to be associ- 
ated rather with a peculiar type of sediment than with a definite time 
period of narrow limits. Neither the Ptyctodus nor the Spathiocaris 
have been found in the basal Kinderhook shales at Burlington, but the 
fauna of the basal portion of the formation is of course not known. 
During the progress of Kinderhook time the sea was encroaching 
from both the north and the south, until before the close of the epoch 
free communication was established between the earlier separated 
provinces and the fauna of the southern province became the dominant 
type throughout the entire Mississippi Valley Basin. ‘This northern 
incursion of the southern fauna is well exhibited in the uppermost 15 
feet of the Kinderhook section at Burlington and elsewhere. 
From the outline of the faunal history here given, it is evident that 
the arrangement of the Kinderhook formations into three successive 
t Mo. Geol. Surv., XII, 77. 
2 “Bed No. 4, Stewart,’ Kansas Univ. Quart., IV, 161. 
