GEOLOGICAL AND NATURAL HISTORY SUH\TEYS. 211 



tinuing to a greater depth unless it were decided to penetrate to 

 the Onondaga salt formation. On the 11th of February, 18G0, a 

 similar series of well borings at Grand Eapids, reaching to the depth 

 of 490 feet, was submitted to the State geologist for examination. 

 These had been preserved by A. O. Currier, E. E. Butterworth, and 

 Martin Metcalf. On this occasion the State geologist delivered a 

 public address in Lyceum Hall, in which he set forth, witli greater 

 fullness than before, his conception of the geological relations of 

 Michigan brines. 



On February 7 tlie East Saginaw Salt Manufacturing Compan}' 

 presented a formal report, in which their enterprise was pronounced 

 a complete success. The hole was3{- inches in diameter, and had been 

 sunken to a depth of G40 feet, at whicli point the brine obtained 

 lacked over 10 salometer degrees of saturation. This well was subse- 

 quently extended to GG9 feot, reaching brine within G° of saturation; 

 and a sub'^equent larger well was carried to a depth of 80G feet, pass- 

 ing quite through the Marshall sandstone. This was the point which 

 the State geologist had previously fixed at about 800 feet. 



On February IG, 18G0, the Saginaw Evtevprhc published a report 

 from the State geologist which had been addressed to Dr. H. C. 

 Potter, one of the directors of the East Saginaw Salt Manufacturing 

 Company.* In this, an attempt wns made to correlate the geology of 

 the well borings at Grand Eapids and Saginav/ with the observed 

 geology of the State as studied at the outcrops. It supplied the first 

 published statement of the stratigraphy of the lower peninsula under 

 the conceptions which had been based on the observations of 1859. 

 As a historical memorandum it seems to be worthy of reproduction 

 in this sketch. 



Rock Formations as Obskrved in 1S59. 



I. CARBONIFEKOUS SYSTEM. 



1. Conl measures, consisting of — 



(rt) Woodville sandstone (the "overlying" sandstone). 



(ft) Shale, coal, fire clays, sandstones, ironstone, etc. 



(c) Parma sandstone. 



(rt) Cherty sandstone (probaby the coal "Conglomerate"). 



2. Carbonifeions limestone: 



(a) Upper (not seen south of Grand Ilapids). 



(ft) Red, arenaceous limestone, .5 feet. 



(c) Lower (Grand Rapids. Bellevue, Parma, Spring Arbor, etc.). 



3. Gypseous series (shales, clay, cherty limestone, gypsum, salt). 



4. Napoleon sei'ies, consisting of— 

 (a) Napoleon s:indst(me. 



(ft) Striped sandstone. 



(c) Ironstone (net universal), 4 inches. 



» Thi.s wns also included in tiic ronort of ttie directors to the stoclvholdors. 



