PREFATORY NOTE. 



^lie materials composing- the following report were not accessi- 

 at the time my annual report was printed, and are now issued in 

 form of a supplement. Full descriptions and illustrations of the 



y and little known species will appear in the final reports, now in an 



^anced state of preparation. 



F. V. HAYDE]^, 



United States Geologist in charge. 

 ""FFiOB U. S. Geological Survey of the Territories, 



Washington, May 13, 1872. 



