LETTER OF TRANSMITTAL 



Department of the Interior, 



United States Geological Survey, 



Washington, D. C, April 23, 1898. 



Sir: I transmit herewith the manuscript and illustrations of a mono- 

 graph upon the Crystal Falls Iron-bearing District of Michigan, by 

 J. Morgan Clements and H. L. Smyth. The district is thus called from its 

 principal mining town. The area reported upon connects the Marquette 

 district on the north and the Menominee district on the south. 



This monograph is one of the series which is to treat of the iron-bearing 

 districts of the Lake Superior region. The first of the series was that on 

 the Penokee district (Monograph XIX); the second of the series was that 

 on the Marquette district (Monograph XXVIII). The present report is the 

 third of the series, and the report upon the Menominee district, now being 

 prepared by W. S. Bayley, will be the fourth. 



No jDrevious detailed report has been issiied u^jon the Crystal Falls 

 district, although the area has been touched upon by Messrs. T. B. Brooks 

 and Carl Rominger. The present report is the first which contains 

 geological maps and sections of the district. 



The field work upon which the present report is based began about five 

 years ago. The work of the first season was a topographical survey and a 

 reconnaissance geological survey. The work of the second season was 

 detail geological work by H. L. Smyth, W. N. Merriam, and their assist- 

 ants. The work of these two seasons was done for private parties. These 

 parties turned over to me the original specimens, notes, and maps to assist 

 in the preparation of this report. The detail geological mapping of the 

 second year had covered only a part of the area included within the present 

 report, and in the remainder of the area in the following years detail 

 surveys were made by J. Morgan Clements and W. S. Bayley. 



