Axelrod: The Pliocene Verdi Flora of Western Nevada 95 



19° F. Thus the area is typified by a cold, semiarid, continental-type climate, with 

 the hot summer days typically cloudless and with the cold winters bringing low 

 temperature and light precipitation. 



Acknowledgments 



The Carnegie Institution of Washington provided funds for field work to secure 

 a large Verdi collection in the late spring of 1939. A preliminary report on the 

 flora was assembled at the U.S. National Museum during tenure as National Re- 

 search Fellow in 1939-1941, but completion of the study was interrupted by war. 

 The Committee on Research, University of California, Los Angeles, granted funds 

 to defray the cost of illustrating the fossils. The final part of the field work was 

 carried out with a grant from the National Science Foundation as part of broad 

 study of the Late Tertiary floras in western Nevada. For assistance in collecting 

 I am indebted to my wife, Nancy, and to James F. Ashley and Robert E. Smith. 

 Thanks are also due Roland W. Brown for permission to study the small but im- 

 portant Verdi collection in the U.S. National Museum, and for making available 

 illustrations of three species in that collection which are not represented in the 

 large suite of material in the Museum of Paleontology, University of California. 

 Finally, thanks are extended to Cordell Durrell for help in the identification of 

 the crystalline rocks, and to the Board of Editors in Geological Sciences for their 

 sincere, critical appraisal of the manuscript which has materially improved the 

 paper. 



GEOLOGY 



Investigation of the geology of the Verdi area was undertaken chiefly to determine 

 the position of the flora in the section, and to ascertain its stratigraphic relations 

 to the fragmentary fossil mammalian remains which have been discovered in the 

 area. No attempt was made to map the entire basin, because George A. Thompson 

 has been mapping this and the adjacent region for the U.S. Geological Survey, and 

 the project is nearly completed. Thus it will materially supplement the following 

 brief observations which are based on a three-week field study in the vicinity of 

 the fossil locality. 



Stratigraphy 



basement rocks 



The basement in this area comprises both metamorphic and granitic rocks. The 

 oldest rocks are the metamorphics that crop out in the vicinity of Fleish, where 

 they dip steeply. The lowest part of the section is made up of approximately 400 

 feet of metasediments including dark-gray hornfels, light-gray marble containing 

 unidentifiable recrystallized marine invertebrates, lime-silicate garnet hornfels, 

 quartz-feldspar-muscovite-andalusite schist, and associated veins of tourmalinized 

 granodiorite which have invaded these rocks. The metasediments are overlain, 

 apparently conformably, by 2,000 feet of black to dark greenish -black basic (andes- 

 ite, basalt) metavolcanics which include both flows and tuffs. The metasediments 

 and metavolcanics at Fleish appear to correspond to the rocks mapped by Lind- 

 gren (1897) on the adjacent Truckee quadrangle as Sailor Canyon formation and 



