50 MESOZOIC FLORAS OF UNITED STATES. 



the most southerly collections were made. Nichols station is on the 

 Southern Pacific Railroad, 7 miles due south of the Thompson Creek plant 

 beds, and the plant localities near this station lie in a north-south line 

 that passes through those on Buck Mountain and ends with the localities 

 on Thompson Creek. The geology of the region near Nichols station is 

 more complicated than that of Thompson Creek, and, as will be seen from 

 the statement that follows, there would seem to be some change in the 

 rock character. 



Mr. Will Q. Brown first discovered plants in the railroad cut near 

 the whistling post for the station, and made a small collection. Pro- 

 fessor Ward says, in speaking of his visit to this locality, that " very little 

 additional to Mr Brown's collection was found in the railroad cutting." 

 It was seen however, that the same slates occur here as in the Buck 

 Mountain district and that they came from the north in a regular way. 

 At this point the course of Cow Creek is nearly along the strike of the slates, 

 and they cross the creek veiy obliquely and follow the bed of the stream 

 for some distance, giving an exposure that permitted a large collection to 

 be made. The points of difference from the exposures farther north are 

 these : The slates near Nichols station are nearly vertical and have a high 

 dip to the east instead of dipping westerly, as on Thompson Creek. They 

 have a thickness of about 200 feet and show^no conglomerate bands. As 

 there had been no continuous tracing of the strata from Buck Mountain 

 to this locality, the stratigraphical work does not show whether or not 

 the plant beds here are identical with those on Thompson Creek. 



From the preceding statements it will be seen that the plants described 

 in this paper come from three regions separated by intervals in which no 

 plants were collected. The Thompson Creek region is separated from the 

 Buck Mountain localities by a comparatively short interval, while the 

 Nichols station localities are much more remote. The collections made 

 at the different spots, at different times and by different persons, are of 

 very unequal value, for thej^ range from only one or two specimens in some 

 cases to hundreds in others. This fact should be borne in mind in noting 

 the distribution of the plants. The absence of a given plant from a 

 particular locality may mean, not that it was really absent, but that the 

 collector failed to obtain it in his imperfect search. In order that some 

 idea may be had of the great difference in the size of these collections I 

 will give a brief account of them, stating the localities from which they 



