Axelrod: The Pliocene Verdi Flora of Western Nevada 125 



MAMMALS 



Although fragmentary remains of mammalian fossils (chiefly broken limb bones) 

 have been found at several sites in the Coal Valley formation in the Verdi region, 

 at the present time only three specimens are known which provide evidence of age. 

 The mastodont tooth described by Buwalda (1914) comes from a locality approxi- 

 mately 1 mile southwest of the Verdi flora, and about 500 feet above it strati- 

 graphically. In view of the fragmentary nature of this fossil, which Buwalda 

 identified as Tetrabelodon ( ?), his discussion of its age significance was necessarily 

 indefinite though he seemed to consider it Late Miocene. Stirton (1939, p. 635) has 

 pointed out that it does not differ appreciably from certain Lower Pliocene speci- 

 mens in the San Francisco Bay region which have been referred to fTrilophodon 

 simpsoni. However, he stressed the fact that the tooth is not diagnostic in terms of 

 close age assignment. In a recent discussion (Sept., 1956) he has indicated that it 

 could well be Middle Piocene (Hemphillian). 



Another mastodont tooth, now in the museum of the Mackay School of Mines 

 at the University of Nevada, comes from Mogul east of the flora, and approximately 

 600 feet lower in the section. According to Donald E. Savage (written communica- 

 tion, Jan. 17, 1956) : "... It is a left M 2 of a mammutid (true) mastodon. It can 

 be called Miomastodonf or Pliomastodonf ; both are rather intangible subgenera of 

 Mammut. Age. Barstovian to Hemphillian, possibly Clarendonian from meagre 

 evidence. The tooth shows some differences from the Pliomastodonf of the Smith's 

 Valley fauna but could be the same." The Smith's Valley fauna is considered 

 Middle Pliocene (mid-Hemphillian) by vertebrate paleontologists. 



A fragmentary lower premolar of a Hipparion or a Neohipparion was collected 

 in the spring of 1951 by Ira LaRivers, of the University of Nevada, at a locality 1 

 mile north of Mogul, where it occurs in the upper member, about 400 feet below 

 the flora. R. A. Stirton examined the specimen and has reported (written com- 

 munication, May 1951) that it is evidently of Pliocene age. 



It is apparent that the Middle Pliocene (Hemphillian) age of the Verdi flora, as 

 deduced from paleobotanical evidence, is supported by the age implications of the 

 fragmentary mammalian fossils that are now known in the Verdi basin. Since the 

 highest part of the Coal Valley section, which is exposed along the highway at the 

 west edge of Reno, is stratigraphically not less than 1,500 feet above the Verdi 

 flora, those rocks may well range into the Upper Pliocene (Blancan). 



SYSTEMATIC DESCRIPTIONS 



Family CHARACEAE 



Chara verdiana n. sp. 



(PI. 18, fig. 2) 



Description. — Terminal branch 7.5 cm. long, stem 1.0 mm. wide, divided into nodes and long 

 internodes spaced from 7 to 8 mm. apart in the middle and lower parts of the axis, somewhat 

 shorter above; lateral branches whorled, rather numerous at the nodes, 5 mm. wide or less, and 

 up to 1.7 cm. long; tips narrowly acuminate. 



