104 THE GEOLOGY OF MINNESOTA. 



[A. Winchell, 1871. 



them feldspar-porphyry, with magnetite and epidote, and also calcite and 

 laumontite, some of the rock being amygdaloidal. Between the hyperyte 

 and the porphyryte he notes another unstratified homogeneous black rock, of 

 igneous origin; but he essays not to trace the relations which these igneous 

 rocks bear to each other, though he states that they seem to be inter- 

 stratified with the Potsdam sandstone at points farther down the coast. 



The "trap rock" at Taylor's Falls he styles porphyryte, places it in the 

 Huronian, and dissents from Dr. Owen, who regards the sandstone overlying 

 as older than the trap. Mr. Kloos, on the other hand, demonstrates, by 

 various diagrams and by his observations, that the sandstone was deposited, 

 and still remains undisturbed, in horizontal stratification, unconformably, 

 over the crystalline rock, and must be of later date.* 



In respect to the copper discoveries at Taylor's Falls, he says that there 

 are a great many small feldspathic veins, and that in one of these, where 

 Mr. Taylor had sunk a shaft to the depth of twenty feet, copper was dis- 

 seminated through the substance of the vein-rock (principally feldspathic 

 and decomposed) in exceedingly thin foliae, mixed sometimes with a sul- 

 phuret of copper, or copper-glance. The Kettle river discoveries he regards 

 more favorably. They are forty miles above Taylor's Falls, and warrant 

 the expectation that in other places on the Kettle river copper-bearing 

 veins will be found at some future time.f 



Mr. Kloos was the first to announce the Cretaceous rocks at any point 

 so far north in the state as the Sauk valley. In the American Journal of 

 Science and Arts, 1872, he gives the particulars of such a discovery, authen- 

 ticated by paleontological determinations of Mr. F. B. Meek. 



A. WINCHELL EXAMINES THE SALT WELL AT BELLE PLAINS. 



The legislature ot 1870 passed a law entitled " An act to aid in the 

 development of the salt springs at Belle Plaine," which donated six sections 

 of the state salt lands to a company organized for that purpose, on certain 

 conditions. These conditions, which required the sinking of a drilled well at 



*In the third volume of the report of the geological survey of Wisconsin. Mr. Sweet seems to have come to the 

 same opinion independently, ata later date than Mr Kloos. 



fSubsequently Mr. Kloos and Prof. Strong made a careful examination of the crystalline rocks collected in Minne- 

 sota. Mr. Kloos' geological observations were published in Zeiischrifl d. d. geol. Gesellschaft, 1871, S. 428; and the min- 

 eralogical papers of Strong and Kloos are to be found in the Neues Jahrbuch fur Min. Geol. u. Pal. 1877. Vide, also, the 

 translations of these in the tenth and eleventh annual reports of the Geological and Natural HUtory survey of Minnesota. 



