192 Miscellanies. 



gypsum, &c. The red sandstone of the graywacke group rises 

 at the pictured rocks on Lake Superior, in a mural precipice of 

 two hundred to three hundred feet high. Gypsum appears above 

 the surface, and probably exists in large masses in Kent county. 



There are numerous salines and salt springs in Michigan, and 

 a copious table is annexed, exhibiting their contents, and com- 

 paring them with those of salt waters in New York, Ohio and 

 the Atlantic ; it is obvious from this comparison, that the salines 

 of Michigan may hereafter prove very valuable, but as yet they 

 have been little developed. The temperature of the different 

 springs was from 48° to 51° Fah.,* while that of fresh water in 

 the vicinity was usually about 50°. In Michigan, as elsewhere 

 in the west, the Indians were acquainted with the salines, and 

 extracted the salt in a rude manner. The wild animals also 

 found their way to these licks, (as they were called,) and their 

 paths often gave the first information of the existence of the 

 springs. 



Nearly the whole western coast of the peninsula next to the 

 lake, is bordered by a succession of sand dunes or hills of loose 

 sand, not unfrequently attaining a considerable altitude, partly 

 naked, and in part covered by dwarf pines and cedar, and should 

 these be thoughtlessly removed, the sands might drift, and prove 

 a serious evil. 



Marls are common, especially in the northern parts of St. Jo- 

 seph's, and the adjoining counties. Bog iron ore exists in vast 

 quantities near Kalamazoo and Detroit, and other places. There 

 are sulphureous springs in Monroe county ; and near Havre there 

 is a spring of this description, whose circumference is one hun- 

 dred and fifty feet, its depth thirty five, and the stream is suffi- 

 ciently copious to turn a mill. 



Topographical maps of the several counties are in the course of 

 preparation, and the geological survey will be prosecuted, we 

 trust, with vigor and success. 



In addition to Dr. Houghton, the corps consists of Ab'm. Sager, 

 principal assistant in Zoology and Botany ; S. W. Higgins, To- 

 pographer and Draftsman ; Columbus C. Douglass, Sub- Assistant ; 

 Bela Hubbard, Sub- Assistant ; William P. Smith, Sub- Assistant, 

 in charge of Mechanical Zoology. 



* In one case, 46°. 



