GEOLOGICAL SURVEY OF THE TERRITOEIES. 43 



and ground up into materials for rocks of more recent date by the waters 

 of subsequent oceans. 



Then, again, between the Coal-Measures and the Cretaceous rocks, as 

 shown in the illustrative section, the two great ages, Triassie and Juras- 

 sic, are not represented at all. 



We have reason to believe that rocks belonging to these eras were 

 even dei^osited here, and yet every trace of them has been washed 

 away. 



In Kansas, on the Smoky Hill Fork, there are a series of variegated 

 beds of clays and sands interposed between the Permian and Cretaceous, 

 which we believe belong to the Triassie or Jurassic period, or both. 

 Along the eastern slope of the Laramie, Big Horn, Wind Eiver Mount- 

 ains, and the Black Hills of Dakota, the red beds of the Triassie and 

 the marls and marly limestone of the Jurassic eras are developed to a 

 thickness of several hundred feet, while on the Platte not a trace of 

 them is to be seen. 



The evidence seems to me to be clear that beds of greater or less 

 thickness, belonging to all these periods, once existed in this region, 

 and that they have been swept away by the erosive action of water. 



This subject, which is one of the most interesting as well as important 

 in the geology of the West, will be discussed more fully in the final 

 report. 



Like all other portions of the State, the interest in the discovery of 

 workable beds of coal in this region is very great. Along the Platte a 

 seam of Carboniferous shale crops out, occasionally twelve to eighteen 

 inches in thickness, and wherever it occurs it is regarded by the settlers 

 as a sure indication of coal. I have examined all the indications with 

 care, and I see no evidence of any coal at a reasonable depth. I hold 

 the same opinion now that I expressed in a scientific paper in 1858, that 

 I was " inclined to the belief that it was a geological impossibility for 

 a workable bed of coal to be found within the limits of the Territory of 

 Nebraska. A bed of coal, to be really valuable for economical purposes, 

 should be at least three feet in thickness; and even then it would not 

 prove profitable if a large amount of labor were required in opening the 

 mine." 



The several beds of limestone have been opened for twenty-five or 

 thirty miles along the Platte, and the greatest abundance of the best 

 building-material can be procured. Duclos's quarry, on the farm of Mr. 

 J. I. Paynter, township 13, range 13, section 27, there is the following 

 section : 



6. Yellow marl, a superficial recent deposit. 



5. Yellow clay, full of white lumps, like magnesia pebbles. 



4. Three or four layers of limestone, excellent for building jmrposes, 

 varying from ten to fifteen inches in thickness each ; five feet. This 

 bed is most extensively quarried; the rock is a great favorite with ma- 

 sons. Its upper surface has been smoothed by glacial action. 



3. Slope ; doubtless intercalations of clay and thin beds of rocks ; 

 thirty feet. 



2. Heavy layers of limestone, yellowish-white, full of organic remains, 

 as, 8. cameratus, Productus, Athyris, Fusulina, »&c. ; ten to fifteen feet. 



Although this rock is not quite as good as that in bed four, yet it is 

 much used for lime and for building purposes. 



1. Sloi)e ; probably same as bed 3, twenty-five feet above the bed of 

 the Platte. The surface of bed 4 exhibits some very remarkable phe- 

 nomena, which I have observed in very few localities in the West, and 

 nowhere except in this region. It has been so thoroughly smoothed by 



