BROWN AND REDWOOD COUNTIES. 579 



C'retaceous lignite.] 



"No. 13 is a specimen of dark colored clay containing an unusual amount of organic com- 

 bustible matter, not enough, however, to give it any value as fuel. It burns to a very light-col- 

 ored ash consisting largely of alumina, and would therefore in all probability make very good 

 brick if sufficient sand were mixed with it. The results of analysis were as follows: 

 Specific gravity, 1.968. 



Water ] 



Volatile combustible matter j.29.55 percent. 



Fixed carbon J 



Ash, consisting of clay 70.45 " " 



100.00 " " 

 The ash contained 

 Insoluble portion, consisting of insoluble alumina and silicic acid. . 92.751 per cent. 



Soluble silicic acid 490 " ' " 



Sulphuric acid -. 282 ' 



Ferric oxide and alumina 2.894 " " 



Lime 1.076 " " 



Magnesia 348 " " 



Undetermined matters 1.159 " " 



100.000 " " 



"No. 14 consisted of a soft, siliceous rock, containing small fragments, grains and specks of 

 mineral charcoal. The results of analysis are as follows: 

 Specific gravity, 2.141. 



Water and combustible matter 26.54 per cent. 



Ash 73.46 " " 



100.00 " " 

 The ash contained 



Insoluble matter, chiefly silicic acid 96.549 per cent. 



Soluble silicic acid 0.836 " " 



Sulphuric acid 0.178 " " 



Ferric oxide and alumina 0.257 " " 



Lime 1.023 " " 



Magnesia 0.4^2 " " 



Undetermined matters 0.695 " " 



100.000 " " " 



It appears nearly certain that no workable deposits of coal exist in this region. Professor 

 Winchell summarizes his observations and conclusions, upon this subject, as follows: 



"1st. The rocks that have been explored for coal, on the Cotton wood and Redwood rivers, 

 belong to the Cretaceous system, and do not promise to be productive of coal in valuable quan- 

 tities. 



"2d. The coal there taken out is of an inferior grade, though varying from cannel coal to 



charcoal." The charcoal, "while it is the more abundant, is of less value for use as 



fuel. It is light, and quickly ignites It lies in irregular sheets, generally not 



more than half an inch thick when pure, but may be disseminated through a thickness of six or 

 eight feet. It is very fragile, hardly bearing transportation." The cannel coal "is black, or brown 

 black, lustrous, compact, rather hard, and presents every aspect of a valuable coal. It occurs in 

 isolated lumps or pockets, in the same beds as the charcoal, but less abundantly. It readily 

 burns, making a hot fire. In the air, when it has become dry, it cracks and crumbles something 

 like quicklime, but not to a powder." 



"3d. As the rocks of the Cretaceous period are believed to have existed throughout the 

 most of the state, the only probable exception being in the southeastern portion, including half a 

 dozen counties, such coal is likely to occur at a great many places. 



"4th. The 'float' coal which has so often attracted the attention of the people, is derived, 

 so far as yet known, from the disruption of the Cretaceous rocks by the glaciers of the ice'period. 

 It is scattered through tlie drift, and is met with in wells and other excavations, and may be often 

 picked up along the beds of streams." 



