154 The American Geologist. March, 1902 _ 
i. b. OXYCHLORIDE CEMENTS. 
Oxychloride Cements. “In 1853 Sorel discovered the fact 
that zinc chloride mixed with zinc oxide united therewith to 
form a very hard cement. A solution of magnesium chloride 
in like manner sets with magnesia, the product being in both 
cases an oxychloride.”* . 
Though cements of this class cannot well be put on the 
market as cements, the property above noted has been taken 
advantage of in the manufacture of a number of patented artt- 
ficial stones, the exact methods followed varying with the dif- 
ferent processes. “Sorel stone,” one of these, is frequently 
quoted in engineering text-books, but has never come into any 
prominent use as a structural material. 
SKETCH OF THE IRON ORES OF MINNESOTA,.+ 
By N. H. WINCHELL, Minneapolis, Minn. 
CONTENTS. 
Early opinions of its ExXistenCe........:...ceeeeeee cceeeweeeeecesenereeees 154 
Acttral Exploration .......ccccccceeee ices ceecseeseceeceeeersecteceseesscsecenes 156 
Annual production ..........c.cccee ceeeeeceeeeeceeeaeecenecnesnenceneeeareeeees 157 
Minnesota Surveys’ AQCNCY..ccccccccececee seceeceesees seserecereesenees 156 
Geological relations...........sccsesrscesscecenececsseeseees soseeecenecseoeens 157 
Origin of the ores. History of opinion. Irving, Wads- 
worth, Spurr, the writer ........ccccccsseccsee csccececencesecseveneres 159 
Prospect Of GiSCOVETICS...0....c..cceceerceceeeeereneeeeenecesene scenes enee ee 161 
Conteh welOn via cceciesd scatavcvvaccedenduscccsckes uavvunveswscvehsueswehltnaberieann 162 
The first published references to iron ore of commercial 
value in Minnesota were by geologists in the employ of the 
State or of the United States. Charles Whittlesey, of Ohio, 
was connected with the United States Geological Survey of 
D. D. Owen, in 1848 to 1850, and examined the region now 
containing these ores. Hypothetically he stated that the geo- 
logical structure warranted the expectation of iron ore north 
of lake Superior, but he did not see it, and his opinion was not 
published till 1866,+ after the State of Minnesota had instituted 
its own survey under ‘Hanchett and Eames. 
*THorre, T. BE. Dictionary dsoited Chemistry, 3rd ed. 1894, vol. i, p. 485. 
+ Paper read +4 Boise City, Idaho, before the Iuternational Mining Con- 
gress, July 24, 190 
t Report of Ss scethoss in the Mineral regions of Minnesota during the 
years 1848, 1859 and 1864. Cleveland, 1866, p. 10. 
