120 THE MICROSCOPE. Aug. 



The Feldspar, on the northeast, when decomposed 

 formed the clay and was mostly albite or soda feldspar 

 with some orthoclase or potash feldspar, and the sand 

 was quartz sand which is found now in the clay. This 

 clay covered the country from Nova Scotia to the borders 

 of New Jersey on the east of the Appalachian mountains. 

 How far it goes west towards the Rocky mountains has 

 not been determined but it is most likely the same. 



The bacillariacese, or diatomaceous earths, which are 

 known as fresh water, fossil, sub-peat or lacustrine sedi- 

 mentary deposits, many of which I examined for the 

 State Greological Survey of New Hampshire, under Prof. 

 Charles H. Hitchcock, and the Northwest Boundary Sur- 

 ver for Mr. George Gribbs, and the State Geological Sur- 

 vey of California, under Prof. J. 1). Whitney, are exam- 

 ples. How far to the west of the Appalachian mountains 

 they extend I do not know, but two of them have been 

 sent me by Mr. B. W. Thomas, of Chicago, and both are 

 from the same iceberg period, containing precisely the 

 same bacillariacese. These are between the first and 

 second moraines of the western geologists ; but we must 

 say that Prof. G. H. Wright has endeavored to prove 

 that there was but one glacial period and the two 

 moraines were but one, formed at different parts of the 

 same glacial period. I am disposed to side with Prof. 

 Wright. The first that Mr. Thomas sent me was from 

 Minnesota and was from Prof. N. H. Winchell, whilst 

 the other was from near Chicago. 



Typhoid Fever. 



By ELMER LEE, A. M., M. D. 



CHICAGO, ILLINOIS. 



Recognition of the value of cleanliness represents the 

 most practical discovery in treatment during the present 

 generation, and, at the same time it constitutes one of the 



