W. M. Fontaine — Mesozoic Plants from California. 273 



Art. XXXIX. — Notes on some Mesozoic Plants from near 

 Oromlle^ California ; by Wm. M. Fontaine. 



[Published by permission of the Director of the U. S. Geological Survey.] 



During the season of 1894, Mr. T. W. Stanton made a 

 small collection of fossil plants from near the Banner Mine in 

 the vicinity of Oroville, California. They were sent to Mr. 

 Lester F. Ward and by him submitted to me for determination. 

 As the plants indicated an interesting flora, not hitherto known 

 in the Mesozoic formations of America, suggesting, possibly, 

 the existence of true Jurassic plants in the IJnited States, Mr. 

 Ward visited the locality in September in 1895, for the express 

 purpose of making, if possible, additional collections. He was 

 so fortunate as to iind, in the same vicinity, exposures of the 

 strata, unknown to Mr. Stanton, that were rich in fossils. Mr. 

 Stanton's imperfect collection left the age of the formation 

 yielding the plants in considerable doubt, which the larger one 

 of Mr. Ward with its better preserved impressions served in 

 large measure to remove. Mr. Ward's specimens also were 

 submitted to me, and it is the object of this paper to briefly 

 give some of the results obtained from the study of all the 

 material now in hand from Oroville. 



In order that the reader may have some idea of the occur- 

 rence of the fossils, it will be necessary to give a few prelimi- 

 nary statements regarding the geology of the region. 



Mr. Ward collected from four localities, all in the immediate 

 vicinity of the Banner Mine, and in these are included those 

 that afforded the plants of Mr. Stanton. The plants were all 

 found on the same geological horizon. As Mr. Ward informs 

 me, the strata yielding the plants occur in a narrow belt, a few 

 hundred yards wide, with a dip of 70°-80°. They resemble, 

 lithologically, the Jurassic Mariposa Slates, but, as they have 

 hitherto yielded no fossils, and are connected stratigraphically 

 with no known formation, their age is, as yet, not determined. 

 Mr. W.. H. Turner in a paper, " On the Age and Succession of 

 the Igneous Rocks of the Sierra Nevada, " published in the 

 Journal of Geology, vol. iii, No. 4, May-June, 1895, p. 394, 

 in speaking of the eruptive rocks of the S marts ville area, says, 

 " These rocks, largely augite porphyries and their tuffs, are 

 presumed to have covered, as with a mantle, the underlying 

 Paleozoic formations. There are some streaks of slate among 

 the eruptive masses, but these have not, in the Smart ville area, 

 afforded any fossils. However, during the past season, in the 

 northern extension of the same area, in a belt of clay slate 

 interbedded with augite breccia and tuff", fossil plants were col- 

 lected by T. W. Stanton. The exact locality is, by the stage 



