XX11 REPORT OF THE STATE GEOLOGIST, 



correction of their chains. This is marked by monuments in the Texas 

 Base Line. 



That portion of the work which was finished appears with the report 

 of Prof. Streeruwitz on the geology of his district. 



CENTRAL MINERAL REGION. 



The topographic work in Dr. Comstock's district was carried on by 

 Mr. J. C. Nagle, and is intended to furnish, in connection with the 

 work of the United States Geological Survey, the accurate topography 

 of the entire area of the rocks older than the Coal Measures in Central 

 Texas, as a basis for mapping the complicated geology of this region. 

 The work was carried as far as possible in the time allowed by the 

 present field season, and the map as far as completed accompanies this 

 Report. 



In September Mr. Nagle was elected Assistant Professor of Engineer- 

 ing at the Agricultural and Mechanical College of Texas, and the com- 

 pletion of the plotting of the map has been done by him without cost 

 to the Survey. 



MAP OF TEXAS. 



The map of Texas used in the First Annual Report was printed from 

 the plates belonging to the United States Geological Survey, by permis- 

 sion of Major Powell. As it was necessary for us to have maps of the 

 State on several different scales, we began early in the year to collect 

 materials for getting as correct data as possible for use in construction. 



Maps of each county were sent to the respective county surveyors 

 and all required alterations noted. These were compiled on a post 

 route map of the State corrected to late date, and the copy from which 

 engraving is to be made was drawn from this corrected base. 



This has been engraved on the following scales for the use of the 

 Survey and the Department of Agriculture : 



T2"6T~2inr> or 20 miles to one inch. 



sasl^oo , or 40 miles to one inch. 



ttfwottj or 100 miles to one inch. 



GEOLOGY. 



EAST TEXAS. 



On March 28th Mr. W. Kennedy was sent into East Texas to con- 

 tinue the work of mapping the iron ores of Cass, Harrison, and other 



