70 REPORT OF THE SECRETARY. 



so long well known as the compiler of maps of the Northeastern States, 

 and latterly by his topographic work npou the United States Coast and 

 Geodetic Survey. Work was commenced among the Berkshire Hills in 

 Massachusetts in July, and carried on until the close of the year, an 

 area of 1,500 square miles having been surveyed, upon a scale of 2 

 miles to an inch. In carrying on this work very material assistance 

 lias been derived from surveys, either by the United States or State 

 authority, or by private corporations or individuals. 



In the Mono Basin, Mr. Willard D. Johnson spent the summer in 

 topographic work, under the immediate supervision of the geologist in 

 charge of the division of the Great Basin. He was occupied the greater 

 part of the season upon a map of the hydrographic basin of Mono Lake, 

 including an area of about 2,000 square miles, and executed on a scale 

 of If miles to the square inch. About half the area is mountaiuous 

 and difficult, including the western slope of a portion of the Sierra 

 Nevada. Local maps were made of the Mount Lyell glaciers, and of a 

 group of ancient moraines at the mouth of Parker Canon. 



The total area covered by the topographic work of the season 

 amounts to about 53,000 square miles. 



Geologic Work. 



Diskdcl of the South Atlantic. — Prof. H. E. Geiger was detailed to 

 investigate the geology of certain portions of Virginia. He spent the 

 early part of July in the eastern part of the State. During that month 

 and August he studied all the formations from the Greenbrier River 

 to the east of Alleghany Station, West Virginia. 



In September he packed and shipped to Washington specimens from 

 the Devonian formations, in Greenbrier County, and transferred his 

 work to Alleghany County, Virginia. He there made a study of the 

 formations, which are well exposed in that section, and procured some 

 •excellent geologic specimens. In October he extended his work from 

 Alleghany County to Rockingham County, Virginia, where he studied 

 the limestone fossils and made a special study of the foldings between 

 the Blue Ridge and North Mountain. He made a careful comparative 

 examination of the limestones of Alleghany and Rockbridge Counties, 

 and at the end of the month came to Washington. The thauks of 

 the Survey are due to Professor Campbell, of Washington and Lee 

 University, who rendered great service to Professor Geiger. 



Prof. Ira Sayles spent the early part of July in the examination 

 ©f caves near Clinch River, Virginia, and the general features of the 

 surrounding region. He then studied the coal beds of Big Yellow 

 Creek, in Bell County, Kentucky, and the dyestone iron deposits a few 

 miles down Poor Valley. In August he continued his work near the 

 Clinch River, especially with the object of ascertaining the extent and 

 direction of the faulting which was displayed there, and also ex- 

 amined the upper Coal Measures of the region, and made a running 



