160 Association of American Geologists. 



made on this subject by gentlemen present. He had digested 

 soils from Maine, New Hampshire, and Rhode Island, with boil- 

 ing water, without discovering more than a trace of potash ; 

 while the method proposed by Mitscherlich of digesting the soils 

 in free sulphuric acid, always gave decided indications of potash. 

 He was led to infer, therefore, that the mica and other minerals 

 containing potassa were by this method decomposed. 



Mr. B. Silliman, Jr. stated, that the soil of the Nile, when 

 treated according to the method of Mitscherlich, gave abundance 

 of potash, but not any appreciable quantity with boiling water ; he 

 was therefore led to believe that the mica, contained abundantly 

 in the soil, was decomposed by the sulphuric acid. 



Resolved, That a committee be appointed to prepare a detailed 

 report upon the subject of soils and mineral manures, embodying 

 as well the fruits of their own investigations as the results arrived 

 at by others, and that the same be presented at the next meeting. 



Drs. C. T. Jackson, Robert Rogers, Mr. M. Boye, Dr. L. 

 C. Beck, Dr. W. Horton, Mr. B. Silliman, Jun., and Prof. 

 Booth, were appointed on the above committee. 



The committee appointed to prepare a plan of business, made 

 a report, which was adopted. 



Prof. Mather asked for and obtained leave to defer his report 

 on " Drift," until the next meeting of the Association ; in the 

 mean time he was requested to make an oral communication on 

 this subject during the present meeting. 



Prof. Locke read a paper " On the Geology of some parts of 

 the United States west of the Allegany Mountains." 



In this paper the author exhibited particularly the points of agreement 

 between the lead region of the upper Mississippi, and that of Derby- 

 shire in England, and between the mountain limestone of Europe and 

 the " cliff limestone" of the west. He showed that the two rocks agree 

 in geological position, in external and chemical characters, in fossil re- 

 mains, and in metallic veins ; being both highly metalliferous and abound- 

 ing in lead and zinc ores occupying vertical fissures. He described the 

 upper, middle, and lower beds of the "cliff limestone" of the lead region 

 of the west as differing somewhat in characters and in fossil remains, and 

 suggested the inquiry whether these three beds, together with the blue 

 fossiliferous limestone which underlies them, (the probable equivalent of 

 the Trenton limestone,) and the alternations of the lower magnesian lime- 

 stone with the saccharoid sandstone, found at Prairie du Chien, should be 

 considered distinct formations, (as their fossil remains would to some extent 



