MICHIGAN ACADEMY OF SCIENCE. 29 



ally reduced to strontium sulphide, which, when acted upon by an acid and even by 

 water under some conditions will liberate hydrogen sulphide. Oxidation of the hydro- 

 gen sulphide will, of course, then give rise to the sulphur. That the sulphur should be 

 associated with celestite is, hence, self evident. 



The enormous deposits of sulphur at Girgenti and vicinity on the Island of Sicily have 

 been explained by some in a manner analogous to the above, namely, by the reduction of 

 gypsum (CaS04, 2 H .^ O) to the sulphide, and the liberation and subsequent oxidation 

 of hydrogen i ~ sulphide. 



Although the evidence at hand, thus far, seems ample to support the theory advanced, 

 this paper must be considered as merely a preliminary report. The investigations are 



being continued. 



Mineralogical Laboratory, 



University of Michigan. 



ON THE OCCURRENCE AND DISTRIBUTION OF CELESTITE 



BEARING ROCKS. 



EDWARD n. KRAUS. 



[Abstract] 



The study of the rocks — shales and dolomitic limestones — of the upper portion of the 

 Salina epoch in Central New York shows that celestite occurs quite widely disseminated 

 throughout them (1) in the form of well developed crystals and (2) in small circular spots. 

 The celestite was no doubt deposited simultaneously with the rock material. The rocks 

 on the Island of Put-In-Bay, Lake Erie, and in southern Michigan, especially those at the 

 Maybee quarry, Monroe Co., show a similar occurrence of celestite. When ceiestite-bearing 

 rocks are leached by the action of circulating water the celestite passes quite readily into 

 solution and the rock then assumes a porous character; in this manner the so-called " vermic- 

 ular limestones" of New York and also the "gashed" and "acicular" dolomites of Mich- 

 igan may be explained. Such celestite rocks are also the source of the large deposits of 

 celestite which are so abundant in the islands of Lake Erie — especially Put-In-Bay — 

 and at the Maybee quarry, Monroe Co., Mich. 



The paper has been printed in full in the American Journal of Science xviii, 1904, 30-39; 

 xix, 1905, 286-293. — Mineralogical Laboratory, University of Michigan. 



RELATION OF LAKE WHITTLESEY TO THE ARKONA 



BEACHES.* 



BY F. B. TAYLOR. 



The studies of 1904 ou the glacial drift and lake deposits of south- 

 eastern Michigan have shown that the history of the glacial lakes has 

 been more complex than supposed. It has been the belief hitherto that 

 all the principal changes of the glacial waters in the Erie and Huron 

 basins were changes to lower levels, produced in each case by the 

 uncovering of a new and lower point of discharge by the retreating ice 

 sheet. It has been found that in one case, at least, the order of change 



iCompare Bischof, Chemische Geology. 



2R. Brauns, Chemische Mineralogie, 1896, 384, 389, also, J. F. Kemp, The Mineral Industry, 1893, 

 585. 



* Puhlishefl by permission of Professor T. C. Cliamberlln. A more extended account will appear 

 in the Journal of Geology. 



