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University of California Publications in Geological Sciences 



their probable distribution in the region. The pine cones and fir scales occur chiefly 

 in the coarser sandstones, associated usually with carbonaceous layers. It was also 

 in these local concentrations of plant debris that the majority of the pine and fir 

 needles were found. In addition, the coarser sands, which contain most of the re- 



TABLE 1 



Quantitative Representation of Species in the Verdi Flora 



(Unless otherwise indicated, all records represent leaf impressions) 



Fossil species 



Per cent 



Populus alexanderi 



Populus pliotremuloides 



Abies concoloroides 



needles: 28 



cone-scales: 6 



Salix truckeana 



Populus subwashoensis 



Pinus florissanti 



cones: 8 



cone-scales: 5 

 Pinus pretuberculata 



cones: 3 



fascicles: 10 

 Pinus prelambertiana 



cones: 1 



fascicles: 3 

 Prunus moragensis 



leaves: 3 



seeds: 1 



Quercus renoana 



Salix boisiensis 



Arctostaphylos verdiana 



Quercus wislizenoides 



Ceanothus precuneatus 



Chara verdiana (branchlet) 



Nymphaeites nevadensis (rootstock) 



Quercus prelobata 



Ribes galeana 



Totals 



92.1 

 2.2 

 1.6 



1.2 



0.7 

 0.6 



0.6 



0.2 



0.2 



0.1 



0.1 



0.2 



0.2 



100.0 



mains of forest trees and shrubs, are typically cross-bedded, and show current 

 marks, graded bedding, and scour-and-fill structures. By contrast, the finer sand- 

 stones in which the dominants of the flora are preserved display the features of 

 more nearly quiet-water deposition. The coarser sandstones intercalated in this 

 section thus appear to represent flood deposits. On this basis, the needles and 

 cones, together with the associated carbonaceous layers, are interpreted as debris 

 carried into the lowlands from valleys bordering the basin at times of high water. 

 Similar concentrations of drifted material can be seen today along floodplains, 

 and at the foot of fans flanking mountainous areas. The suggestion that the Verdi 



