MEMOIR OF GEORGE H. ELDRIDGE 683 



The opportunity to take up the profession of geologist came through 

 the demand for young men to study the mining industry of the country 

 in connection with the Tenth Census. That undertaking was placed in 

 charge of the newly formed U. S. Geological Survey, and the study of 

 the iron and coal industries was assigned to Professor Eaphael Pumpelly. 

 He applied to Professor Shaler to recommend assistants. Eldridge was 

 one of those chosen, and in the summer of 1879 he entered upon that 

 work. He was assigned to study the deposits of the baser metals in the 

 southern Appalachian region and also the coal fields of northern Montana. 

 The results of this work were published in the Census report, as cited in 

 the appended bibliography (1, 2). 



About the time that the Census work was completed the Northern 

 Transcontinental Survey was organized to examine the mineral resources 

 along the route of the Northern Pacific railroad. This survey was placed 

 in charge of Professor Pumpelly, and Eldridge was naturally one of the 

 first to be employed. He was engaged in this work for about four years, 

 studying especially the coal fields of Dakota and Montana. Owing to the 

 abandonment of the Survey in 1884, much of Eldridge's scientific work 

 of this period never came to publication. The discussion of Montana 

 coal fields in the reports of the Tenth Census embodied much of this 

 information. 



From the summer of 1884 until his death Eldridge was connected with 

 the U. S. Geological Survey. For the first six years of this period his 

 field of work was in Colorado, as assistant to S. P. Emmons. It was as 

 his colleague during these happy years that the writer of this sketch came 

 to know Eldridge and to love him for his many noble and attractive traits 

 of character. 



The principal results of Eldridge's Colorado work, under Mr Emmons, 

 appear in the Anthracite-Crested Butte folio (10) ; in the monograph on 

 the Geology of the Denver basin (15), and in a sketch of the complex 

 stratigraphy and structure of the foothill belt about Golden ( 6 ) . 



The study of the Cretaceous in Colorado and Montana led Eldridge 

 to propose the union of the Fort Pierre and Fox Hills as the Montana 

 formation or group (5). 



In 1890 Eldridge investigated the first productive oil field of the west- 

 ern Cretaceous at Florence, in Colorado, and wrote an account which has 

 served to direct the work of development in that interesting field (7). 



In 1891 Eldri (\ge was given independent work, and his first assignment 

 was to the investigation of the phosphate deposits of Florida. That this 

 study was never completed was not the fault of the geologist; the exi- 

 gencies of Survey work led to his repeated assignment to investigations 



