REPORTS OF GEOLOGISTS. XCV 



tin and prepared at once to resume field work in my own district. Your 

 general instructions to " complete the survey of the Central Mineral Region, 

 including the outlying pre-Carboniferous strata, and such exposures of the 

 Carboniferous as may lie within this area or adjacent to the same upon the 

 east and south," have been carried out as fully as possible in the limited time 

 which could be allowed for the work. The field has now all been explored, 

 by far the greater part in sufficient detail for the construction of a geologic 

 map; but as the area is very much greater than we had supposed, and the 

 facilities for travel in the dry season are rather limited, I have been unable 

 to present a report which can be regarded as final in any permanent sense. 

 We were in the field but three months this year, as against five months in 

 1889. With a larger party, the equipment was reduced from motives of 

 economy, rendering the executive duties more onerous and giving less avail- 

 able time for the geological work. 



The field party was organized as follows : 



Theo. B. Comstock, in charge. 



J. C. Nagle, Topographer. 



Charles Huppertz, G-eological Aid. 



H. B. Jones, Compassman. 



J. F. Clark, Contact Runner. 



H. H. Harris, Rodman. 



R. A. Thompson, Rodman. 



Harry Foster, Hostler. 



Frank Tuttle, Cook. 



Upon the return from the field, September 2, the party was disbanded, 

 Mr. J. C. Nagle and Mr. R. A. Thompson being retained for office work. Mr. 

 Thompson left me to attend the University before the end of September, and 

 soon after Mr Nagle received well merited promotion to the responsible 

 charge of the Department of Civil Engineering and Physics in the State Ag- 

 ricultural and Mechanical College. Mr. Frank S. Ellsworth, at present en- 

 gaged as general assistant, began work October 23, 1890. Mr. G. V. Skelton 

 has been employed since December 5 as draughtsman. 



The region traversed the past season is very largely made up of Silurian 

 rocks at surface, and these afford comparatively few economic minerals, but 

 we have been able to trace out the principal ore belts and to study the limits 

 of the fields in which the mineral resources abound. The map which accom- 

 panies my report for 1890 gives all details of structure and distribution which 

 have been collated to date. 



The method of survey adopted has been somewhat different from the plan 

 followed in 1889, but in essential features it is the same. Each day's work 

 was arranged by myself, the topographers, field assistants and camp men 



