SUPPIiEMENTAl, EEPOKT — HANGING EOCK BISTEICT. 933 



fied deposits, shales, sandstones, fire-clays, coals, fete, aapumulated in 

 these separate localities in the vast lapse of years that one hundred 

 and eighty feet of strata require for their growth. Equality of mf«sure 

 is not, however, to be inferred for other portions of the district. In 

 Greenfield township, Gallia county, the same interval expands to two 

 hundred and twenty feet. Both horizons here are perfectly distinct and 

 certain, and the interval was carefully measured with the engineer's level. 



It will be observed that the whole inte^-vals in the two ipections are 

 divided in very nearly the same way. Especially a Buff Limestone is 

 found in each at a height of about sixty-fiue feet above the baee. The 

 connections of this last named horizon are numerous, and it seems al- 

 most certain that the Buff Limestone of the Hocking Valley is one and 

 the same with the Buff Limestone of Monitor Furnace. There are, 

 however, several limestones of this general character in this part of the 

 series to the northward, and inasmuch as no direct continuity of the 

 stratum has been proved, the identification is not positive. 



This steadiness is all the more surprising when the difference of ma- 

 terials that fill the intervals is considered. There are much heavier 

 sandstones to the southward than in the Hocking Valley. 



A third section is here introduced that represents with great fidelity 

 and minuteness the general stratigraphical order of the series in the 

 southern part of Vinton and the northern part of Jackson counties. 

 This section was furnished by Dr. L. W. Baker, of Hamden Junction, 

 to whose untimely death, reference was made in the letter that introduces 

 this Report. This section stands for a great amount of labor, and a more 

 thorough and accurate knowledge of the field than any other man has 

 ever had. The section was made on entirely independent measure- 

 ments from those already reported, but it is in substantial agreement 

 with them. In regard to the lowermost two hundred feet, it must be 

 granted that there is less certainty than in the other portions. This 

 part of the series has not yet received the attention that it meri.is. 



This report will be concluded with the publication of a number of 

 chemical analyses that have been made in the laboratories of the Ohio 

 State University during the last two years, of the economical minerals of 

 the Hanging Rock District. These analyses will be seen to embrace 

 many points oi interest and importance both as regards quantity and 

 quality. They have been made without expense to the Survey or to the 

 State. The analysis of a few limestones outside of the district is also 

 introduced here, because they are in process of trial as flux among the 

 furnaces of the Hocking Valley. All of these analyses were executed by 

 Curtis C. Howard, B. S., now Assistant Professor of Chemistry in Star- 

 ling Medical College, ColumMs. 



