92 University of California Publications in Geological Sciences 



of Reno, respectively, are of particular importance, for they occur in the Coal 

 Valley formation, which is the eastern fluvio-lacustrine equivalent of the Mehrten 

 formation that accumulated on the west Sierran piedmont. Analysis of these 

 floras can go a long way toward filling a major gap which has existed in our 

 knowledge of the Pliocene vegetation and climate to the lee of the range. This 

 information will make it possible to compare contemporaneous floras on opposite 

 sides of the range, and thus provide a basis for estimating the relative effectiveness 

 of the Sierran ridge as a climatic barrier during the early and middle parts of the 

 Pliocene. In addition, the floras shed considerable light on the evolution of the 

 Sierran forest during the Late Teritary. Since the Verdi and Chalk Hills floras 

 differ markedly in composition and in age, it seems best to consider them sepa- 

 rately. We shall thus turn our attention first to the Verdi flora, and describe the 

 Chalk Hills in a subsequent report. 



Previous Work 



The occurrence of fossil plants in the sediments near Verdi, a few miles west of 

 Reno, was first noted during the survey of the Fortieth Parallel over three-quarters 

 of a century ago (King, 1878, vol. 2, p. 849), but apparently no collections were 

 made. Thirty years later, in his report on the geology and oil possibilities of the 

 Reno region, Anderson (1909, p. 483) referred to a few plants in a small collection 

 recovered "near Reno" which were identified for him by J. P. Smith, and con- 

 sidered Miocene. In the summer of 1914, H. S. Gale made a small but significant 

 collection of the Verdi flora which is now in the U.S. National Museum. Appar- 

 ently a formal report was never issued on this material, which includes three 

 species that are not represented in the collections made subsequently at Verdi. F. 

 H. Knowlton (in Merriam, 1916, p. 167) examined a small Verdi collection in the 

 Museum of Paleontology, University of California, which was secured by John C. 

 Merriam. He identified twelve species, of which six were considered to occur in 

 the Esmeralda flora 150 miles southeast. Knowlton thought the Verdi was the 

 same age as the Esmeralda flora, which was then regarded as Miocene. 



The first large collection of the Verdi flora was made by Ralph W. Chaney in 

 the early 'twenties. I added supplementary material to it in the summer of 1939, 

 and again in 1947, 1953, 1954, and 1956. Since the more recent digging has not 

 turned up any additional species, it is believed that a representative sample is now 

 in hand. Although the flora is small, it nonetheless adds materially to our under- 

 standing of Late Tertiary environment in this region. 



Present Environment 



The Verdi locality is in the Truckee River valley 1 mile east of Verdi, at an 

 elevation of 4,800 feet adjacent to the south bank of the Truckee River. The east- 

 west trending river valley is 2 to 3 miles wide, hemmed in by mountains on the 

 north, south, and west. To northward is Peavine Mountain, whose summit lies at 

 an altitude of 8,244 feet 5 miles distant. To southward, the valley is terminated by 

 the north end of the Carson Range, a subsidiary block of the Sierra Nevada whose 

 rolling summit upland reaches 10,000 feet 7 miles distant. Crystal Peak ridge, 



