GEOLOGICAL SUEVEY OF THE TERRITOEIES. 61 



instances derived from the study of the flora and fauna of the Missouri 

 Valley which go to show this fact. 



In the great lignite basin the molluscous remains, although extinct, 

 have their living representatives in China and Siara. 



The comparison of the flora of the Dakota group, Cretaceous, shows the 

 same relationship of age, and has been alluded to before. Again , these fos- 

 sil remains show that a tropical or subtropical climate prevailed through- 

 out this western country up to a very late period, at least to the close 

 of the Pliocene. 



The prolific flora of the great lignite basin, which is supposed to be 

 of Miocene age, is at least subtropical, or similar to that of our Gulf 

 States. There is a mingling of true tropical and temperate forms. One 

 species of palm was found fossil on the Yellowstone, the leaf of which 

 must have had a spread of twelve feet. At the present time the true 

 palms are found only within the tropics. The faunas of all these depos- 

 its at the different geological periods were tropical in their character, 

 and from these we infer that a tropical climate prevailed over this 

 country during their existence. 



The fertility of the soil of the extended area described in this report 

 is beyond a question. It is for the most part covered with a great 

 thickness of the yellow marl, varying from a few feet to one hundred or 

 more. From Omaha City to the mouth of Niobrara the country bor- 

 dering on the Missouri is quite rugged, or one continued irregular series 

 of rounded hills, as is shown in the accompanying sketch. 



These superficial deposits yield readily to atmospheric agencies, and 

 these hills are formed by the myriads of temporary streams produced 

 by rains. As we go farther into the interior the surface is more undu- 

 lating, yet the drainage is always excellent. 



The superficial marl very readily absorbs the rain, so that even the 

 most level prairie is always sufficiently drained for all the purposes 

 of agriculture. The counties of Washington, Dakota, Blackbird, Cum- 

 ming, Dodge, Saunders, and portions of Sarpy, Douglas, Platte, Stanton, 

 and Dixon, are underlaid by the sandstones of the Dakota group, and, 

 in consequence, a large quantity of silica enters into the composition of 

 the soil, and hence their great reputation in the production of wheat. 

 The average quantity of wheat raised on an acre in the counties above 

 mentioned is from twenty-five to thirty bushels -, forty to fifty bushels 

 not an uncommon yield. 



On one farm in Sarpy County, in 1866, three thousand two hundred 

 bushels of wheat were raised, and the whole average was over thirty 

 bushels per acre. In Burt County, on Omaha Creek, Mr. George Smith's 

 crop averaged forty-three and a half bushels per acre ; Mr. Dugan har- 

 vested twenty-four acres, averaging forty-four bushels. In this region 

 the uplands seem to produce the best grain. Colonel Baird raised this 

 year six acres of wheat that averaged thirty-three and one-third bushels; 

 Mr. Cornelia has taken from an eleven-acre lot, this year, the ninth suc- 

 cessive crop, and it averaged thirty-five bushels ; Mr. ISTeil had twenty- 

 two acres of wheat, averaging forty-three bushels. A gentleman near 

 Tekama, Burt County, hoed in three acres of wheat in 1866, and 

 harvested fifty-one and two-third bushels per acre. 



I have accumulated a mass of statistics in regard to the growth of 

 wheat in this region, and I am convinced that twenty-five bushels per 

 acre is a small yield, while forty to fifty bushels is not unusual. It is a 

 curious fact that wheat raised in this district brings in the market at 

 Saint Louis eight to ten cents more per bushel than wheat exposed for 

 sale from any other State. 



