26 SEVENTH REPORT. 



water power, drilling for oil, mineral water or other resources to replace 

 those that are vanishing. 



The forest then is not wholly gone, and in the place of the part taken 

 are fertile farms, with happy homes, noble buildings, intelligent people 

 and varied industries, and the State is wealthier than ever. 



The one ]>icture is as true as the other (Mr. Hackley's fortune 

 illustrates many of the brighter items) though they are put together 

 like one of Thompson Seton's stories, but I hope^ and think that the 

 brighter picture is the one becoming more true. For this let us all strive 

 as citizens not merely of the kingdom of science and the republic of 

 letters but of the commonwealth of Michigan. 



ON THE ORIGIN OF THE SULPHUR DEPOSITS AT THE WOOL- 

 MITH QUARRY, MONROE COUNTY. MICH. 



EDWARD H. KRAUS. 



From the mineralogical standpoint, the Woolmith quarry, half way 

 between Scofleld and Maybee, Monroe County, is very interesting on ac- 

 count of the occurrence of a very considerable amount of native sulphur, 

 accompanied by its usual associates, celestite, calcite and sometimes gyp- 

 sum. It is not necessary to discuss at this time at any great length the 

 geological conditions at this locality, for they are admirably set forth 

 by Sherzer in his "Geological Report on Monroe County."^ - 



The rocks at this quarry are for the most part dolomites, sometimes, however, quite 

 siliceous, and have been assigned to the Monroe series. Many of the strata contain a 

 relatively large percentage of bituminous matter. It is also important to state that the 

 strata at or near the surface are usually quite compact and vary much in color — from gray 

 to brown — and are more or less blotched or streaked. These compact layers are character- 

 ized by an unusually high specific gravity. Inasmuch as the rock is not homogeneous, 

 different values were obtained. They varied from 2.80 to 3.45. The specific gravity 

 of a normal dolomite ought to be 2.80 to 2.90. This high specific gravity must hence, 

 be considered as indicative of the presence of some mineral, possessing quite a high specific 

 gravity, disseminated throughout the rock. 



As we descend into the quarry the rocks become more porous and cavernous. It is in 

 these layers with cavities, ranging from a few inches up to a foot or more in diameter, 

 that the native sulphur with the associates, indicated above, is found. The occurrence 

 of these minerals is clearly one of secondary formation. 



The rocks near the surface, although compact where they have been protected, show, 

 when exposed, the characteristic structure of leached celestite-bearing rocks which are 

 quite common in the rocks of this series or its equivalent. 2 This, together with the high 

 specific gravity, already referred to, would suggest the presence of celestite. In order 

 to determine the presence of celestite and also its probable percentage, an analysis of the 

 uppermost layer, characterized by Sherzer as Bed A, was made by Mr. W. F. Hunt, assist- 

 ant in mineralogy in the University of Michigan. 



As already indicated, the rock is by no means homogeneous, and hence, in order to obtain 

 as near as possible the average composition of the same, many chips were taken from a 

 specimen of approximately the following dimensions, 4x5x6 inches. The specific 

 gra\'ity of most of the chips was determined and the following are some of the values 

 obtained: 2.80, 2.87, 2.98, 3.17, 3.33, 3.45. 



>W. H. Sherzer, "Geological Report on Monroe countv," Geological Survey of Michigan, 1900, 75. 



2E. H. Kraiis, "Tlie occurrence of celestite near Syracuse, N. Y.. etc.," Amercan Journal of Science, 

 xviii, 30-39, 1904. Also "Occurrence and Distribution of celestite-bearing rocks," ibid, xix, 286-293, 

 1905. 



