24 MESOZOIC FLORAS OF UNITED STATES. 



Further evidence of this is found in the fact that in approaching the 

 general escarpment which bounds these plains the buttes tend to lose 

 their isolated character and form ridges projecting out from the cliffs. 

 It never happens that an entire valley or plain is covered by a single 

 system of buttes. These systems are separated by wide intervals, often 

 of nearty flat country, but through which it can be easily seen that water 

 once flowed, at least in the form of temporary floods, and in such a manner 

 as to have swept away every vestige of the former plateau, and in crossing 

 which there are encountered one or several wide beds to which the term 

 "wash" is popularly applied. In descending the Little Colorado this 

 condition of things, as already remarked, is not met with until within 

 8 or 10 miles of the Lees Feny road. A large system of buttes is then 

 found extending 5 or 6 miles down the river and across the plain to the 

 first terrace, a distance of 3 to 5 miles ; then occurs the first wash, 2 miles 

 in width, followed l^y another system of buttes, which is nearly due east 

 of Tanners Crossing, and in which most of the bones were collected bj^ 

 our party. There is then another wide wash; the next sj^stem of iDuttes, 

 however, does not reach the river, but trends off in a direction nearl}^ due 

 north. There is still another wash before the great Moencopie Wash is 

 reached, the direction of which is such as to l^e highly favorable for the 

 preservation of these buttes, and accordingly we find their greatest develop- 

 ment, so far as this region is concerned, along the Moencopie Wash. 

 They do not, however, follow the stream up in the direction of Tuba, 

 but continue to trend northward along the wide A^alley that lies to the 

 west of Willow Springs and Echo Cliffs. 



The reason why these conditions are not earlier met with in the valley 

 of the river is simply that the river does not follow the line of strike, and 

 these beds, l^eing common to the entire member, lie at different dis- 

 tances from the river. Above the point mentioned, therefore, they must 

 be looked for farther in the interior. We found them, in fact, 5 miles 

 east of Black Falls, or 25 miles southeast of Tanners Crossing. The great 

 bend in the river culminating at Winslow keeps these beds constantly so 

 far to the northeast, in a region where it is very difficult to penetrate, 

 that their exact condition for a distance of over 50 miles is little known. 

 But farther up the river, where they approach somewhat to the region of 

 settlement, they again admit of access, and, as already remarked, they 



