258 
PROCEEDINGS OF THE ACADEJMY OF 
cumstances leading us to suppose from the dip of the strata, that it must pass 
beneath the Cretaceous if continued in a given direction at the same angle of 
inclination, but from the fact that it has actually been seen, directly beneath 
the other Cretaceous rocks, not merely at one place, and by one observer, but 
by several persons at numerous localities. 
In order to satisfy others we are not mistaken in this, we will give a few of 
the many facts in our possession, bearing on this question. In the first place, 
we would remark that the farthest point towards the south at which we have 
seen this formation, is near Smoky Hill river, in Kansas, latitude 38*^ 30' north, 
and longitude 97° 30' west. Here we found it forming the upper part of sev- 
etal isolated elevations known as the " Smoky Hills," at an altitude of about 
1200 feet above the Missouri at Fort Leavenworth. At this locality, however, we 
saw no rocks overlying it, and consequently have no stratigraphical evidence 
that it is the same rock seen by us at other localities under Cretaceous beds ; 
but our lithological and palaeontological evidence is quite conclusive on this 
point, for this rock in color, composition, and all other respects, is undistin- 
guishable from No. 1, of the Nebraska section, as seen near the mouth of Big 
Sioux river on the Missouri, and contains numerous fossil leaves, some of which 
are identical with those occurring in No. 1, at the last mentioned localities. 
Amongst these leaves Dr. Newberry has also identified at least one genus 
(^Ettingshausiania) peculiar to the Cretaceous system. 
Bearing in mind that all the rocks here have a gentle but uniform inclination 
or dip to the north west ; and that the formation under consideration consists 
of red and yellowish sandstones, and various colored clays, with generally more 
or less impure lignite and ferruginous concretions, we will be prepared to recog- 
nize it at lower and lower elevations as we proceed northward. 
Without undertaking to mention in detail the intermediate exposures, we will- 
pass northward at once to localities where it has been seen beneath Cretaceous 
rocks by three different observers at various times ; this is near the Kansas and 
Nebraska line — latitude 40° north, and in the vicinity of 97*=> of west longitude. 
Here at an elevation of about seven hundred feet above the Missouri at Fort 
Leavenworth, or some five hundred feet below the level of the exposures 
mentioned at the Smoky Hills, our deceased friend, Mr. Henry Pratten, saw 
near Wyeth's creek, in 1853, the following exposures in descending order ; 
1st. Slope, thickness not given. 
2nd. Yellow and whitish limestone filled with casts 
of Inoceramus^ referred by him to /. myteloides >No. 3, Nebraska Sec. 
= /. problematicus . J 
3rd. Slope, thickness not given. | No. 2, Nebraska Sec. 
4th. Red ferruginous sandstone with leaves of di- 5 -kt i q„„ 
.11 , ^iNo.i, IN eDrasK.a oec* 
cotyledonous trees. 5 
A short distance west of this exposure Dr. J. G. Cooper informs us he saw 
outcrops of a red sandstone in the valleys at about the same elevation ; and 
above this, exposures of dark gray laminated clay answering exactly the de- 
scription of No. 2, of the Nebraska section, while above the latter, near the tops 
of the hills, he met with outcrops of light colored limestone containing numer- 
ous casts of Inoceramus. 
At other localities not far to the southwest of the foregoing, Mr. Hawn saw ex- 
posures of light colored limestone forty-five feet in thickness, containing great 
numbers of Inoceramus which we referred, from specimens sent by him, to /. 
problematicus. * Below this there was a slope of twenty-seven feet in which 
he saw no exposures, while still lower he observed outcrops of dark ferrugi- 
nous and yellow sandstone, and various colored clays with impressions of leaves 
* It is with some donbt we have referred this species to I. problematicus ; it is the same spe- 
cies described by Dr. Schiel in the second volume of the Pacific Rail Road Report, pyge 108, plate 
3, figure 8. It is rather longer on the hinge than is common in I. problematicue, from which it 
may be distinct. We always refer to this shell in speaking of /. problematicus. 
[Dec. 
