124 KANSAS ACADEMY OF SCIENCE. 
On the 11th, he speaks of some bluffs of yellow sand that extended for 
several miles along the river. A more comprehensive account is given in the 
journal kept by Captain Clarke, as follows: ‘‘We halted on the south side for 
the purpose of examining a spot where one of the great chiefs of the Mahas 
{Omahas], named Blackbird, was buried. A hill of yellow, soft sandstone rises 
from the river in bluffs of various heights till it ends in a knoll about 300 feet 
above the water.’’? 
This was on August 11. The next day the following entry appears, referring 
to some hills a few miles further up the river: ‘‘Four miles beyond this bend a 
bluff begins and continues for several miles on the south; it rises from 20 to 150 
feet, and consists of yellow and brown clay, with soft sandstone embedded in it.’’* 
These three localities are easily recognized to-day. The high banks, first 
mentioned by Sergeant Gass, are the ‘‘ High Banks,’’ a mile north of Decatur, 
Neb. It is a curious coincidence, if nothing more, that the name casually used 
by Sergeant Gass is the one by which the bluff is now known throughout the 
region. Blackbird hill is still pointed out to the traveler through the Omaha 
reservation, and the person who will take the trouble to go up the river a mile 
above the old mission building will find the ‘‘ bluff of yellow and brown clay with 
soft sandstone embedded in it.’’ 
The noted geographer, Nicollet, in his journey up the Missouri in 1839, men- 
tions a number of formations, but seems to have confused the Dakota with the 
underlying Carboniferous. Audubon and Harris, in 1843, Evans, in 1849, and 
Culbertson, in 1850, were either not interested in geology, or else passed the sand- 
stones of this group with a cursory examination, and devoted their time to the 
somewhat better-developed beds of the more recent formations further west.‘ 
It was in 1853 that the first systematic work was done on the Cretaceous of 
the Missouri river, of which the Dakota forms the basal member. Dr. F. B. . 
Meek and Dr. F. V. Hayden, men whose names are inseparably connected with 
the geology of the Northwest, were sent on an expedition to the Bad Lands by 
Dr. James Hall, of Albany. Although the time was spent chiefly among the 
later Cretaceous and Tertiary formations, a comprehensive idea of the whole 
series was obtained. It was during this trip that the first fossil leaves were found 
in the Dakota. 
About this time Prof. Jules Marcou, a French geologist, published a geo- 
logical map of the United States, in which he colored most of the region west of 
the Missouri river as Jurassic.° 
On March 11, 1856, Meek and Hayden read a paper before the Philadelphia 
Academy of Science, entitled ‘‘ Descriptions of New Species of Gastropods from 
the Cretaceous Formations of Nebraska Territory.’’ In a prefatory note they 
discuss briefly the relations of the formations, and give the following section: 
POKING suk {655 sess ad0d oe Meas ke tg eae athe hae Acne ee 400-600 feet. 
Cretaceous: 
No. 5. Gray and yellow arenaceous clays, containing great num- 
bers of marine mollusks with a few land plants.......... =oue LOO-1b0e ** 
No. 4. Plastic clay with numerous marine mollusks............ Jou 
No. 3. Gray and yellow calcareous marl containing Ostrea con- 
esta; fish Beales; QtGstine ee ceenins! sa cate slew o's sions = «Je oles wee 100-150 ‘* 
No. 2. Grayish and lead-colored clays having a few fossils...... 80) 2 
No. 1. Sandstone and clays not positively known to belong to 
the CretaceOus. AGO... func ek wai aan eiceee kp cup oo 01d ae alan Oneal tS 
Upper Coal Measures, limestone at Council Bluffs.® 
2. Lewis and Clarke’s Exp. up Mo. Riv., 1814, 1: 43. 3. Ibid. 
4. Meek and Hayden, Proc. Phila. Acad. Sci., 8: 111, 112. 
5. Bull. Geol. Soc. of France, 1850... . 6. Proc. Phila. Acad. Sci., 8: 63-69. 
