344 Chemical Laboratory, University of Minnesota. 



Contributions from the Chemical Laboratory of The University , 

 of Minnesota. 



ANALYSIS OF A SAMPLE OF MANKATO CEMENT ROCK W. C. SflVjh. 



Insoluble in HCL, 19.22 per cent. 

 Composition of insol. part : 



Silica, SiOo, 1330 per cent. 



Alumina AI2 O3, 3.87 " " 



Peroxide of iron FcaOs, trace 



Lime CaO, 



Magnesia, MgO, " 



Loss, 2.0s per cent. 



19.22 



Composition of part soluble in HCl. 



Calcium carbonate Ca CO3, 48.74 per cent. 



Magnesium carbonate Mg CO3 29.27 



Peroxide of iron, Fe2 O3 1.52 



Alumina, AI2, O3, .30 



Potassium oxide, K- O, .26 



Sodium oxide, Na2 O, .25 



Phosphoric anhydride, P2 O5 .14 



Silica, SiOo .09 



80.57 



April 8th, 1890. 



ANALYSIS OF A MARL FROM NEAR GLADSTONE, MICH. PetCT 



Christitinson. 



acid and organic matter. 



This marl forms a bed, having an area of over 100 acres and 

 a depth of from 2 to 14 feet. It occurs near the northwest shore of 

 lake Michigan, about seven miles from the head of Little Bay 

 de Noc, on the west side of White Fish river. As a rule it is cov- 

 ered with a thin layer of vegetable mold, but at some places it ap- 

 pears at the surface. 



April 8, i8po. 



