148 THE MARQUETTE IKON-BEAKING DISTRICT. 



fused sediments, representing the lowermost beds in the .sedimentary suc- 

 cession. In the second report he does not look upon them as belonging- 

 with the sediments, but believes them always to be later eruptives. Of 

 the two kinds of greenstone the diabases are regarded as the youngei\ 

 They are often found cutting the diorites. The latter rocks, on the con- 

 trary, are old rocks. Although in ii few cases they wei'e observed to 

 contain the remnants of decomposed augite, the greater portion of them 

 are thought to be original rather than secondary rocks (uralitic diabases) 

 derived from diabases by alteration. In this respect the author diifers 

 from those geologists who are inclined to look upon all the diorites of the 

 district as altered diabases. 



As the result of closer investigation, an iron-bearing horizon was 

 discovered in the arenaceous slate group, so that the author now recognizes 

 two ore horizons in the Marquette district instead of one only, as originally 

 was the case. 



HoBBS, W. H. Miueralogical notes. Am. Jour. Sci. (3), Vol. L, 1895, i)ages 

 121-128. 



2. Barite aud manganite from the Lucy mine, Negaunee, Michigan, ijages 

 123-125. 



3. Chloritoid from blocks on tbe south shore of Miehigamme Lake, Michigamme, 

 Michigan, pages 12.5-127. 



The first of these two notes is ])urely mineralogical. The two min- 

 erals described are from the Lucy mine, in the SW. \ sec. 6, T. 47 N., 

 R. 26 W. 



In the second note the author calls attention to the existence of a 

 chloritoid with the composition of masonite in specimens of a phyllite- 

 schist picked up on the south shore of Lake Michigamme. The rock is not 

 known in situ. The chloritoid is the same as that described by Lane, 

 Keller, and Sharpless in 18'J1. 



