U MESOZOIC FLORAS OF rNITED STATES. 



stiatijirapliical and the palconlolopcal points of vicnv. It was my 

 intention at that tinu' to improvo the first opportunity that presented 

 itself to conduct a much more extensive campaign into that region. 

 1 found tlu> country so exceedingly dry in November that 1 imagined, 

 and indeed was told by persons who live there, that sj^ring would ])e a 

 much more advantageous season for such a campaign. 1 therefore 

 decided to make a somewhat exhaustive study of this region, with an 

 appropriate outfit, in the months of May and .lune, l!)()l. 



The discovery that I made on November 14, 1899, of fossil bones 

 neai- Tanners Crossing of the Little Colorado (see first paper, pp. 322-323) 

 seemed to make it one of the prime requisites of such an expedition 

 that it !;)e accompanied by a competent vertebrate paleontologist, 

 well versed in the methods of collecting and preserving fossil bones. 

 When the attention of Prof. H. V. Osborn was called to this subject 

 he manifested a lively interest in it and offered to select a suitable person 

 to accompany me for this purpose. The choice fell upon Mr. Barnum 

 Brown, of the American Museum of Natural History, wdiose success 

 as a collector of fossil vertebrates and as a field naturalist in general 

 has secured for him wide recognition. The United States National 

 Museum, being in need of a series of Triassic l)ones, assumed the respon- 

 sil)ility for this part of the expedition. The rendezvous was at Hol- 

 In-ook, Ariz., on May 7, where an adequate outfit was procured and the 

 expedition started on the 8th. The route followed was nearly the same 

 as that pursued by me in 1899. 



The object was to make as complete a study as possiljle of the 

 geolog}^ and paleontology of the Little Colorado Valley, as it is in that 

 \-alley, or at least in that drainage, that nearly all the older Mesozoic 

 of this part of Arizona is to be found. 



Certain signs of the occurrence of Triassic vertebrates made them- 

 selves known at different points along the route, but only as weathered 

 out on the surface in such a manner that their original source could 

 not he traced. But as soon as we reached the region of vai-iegated 

 marl buttes, some 5 or G miles above the Lees Ferry road, such bones 

 l)egan to be found and their position in the beds located. Nearly three 

 weeks' careful investigation of the entire region in which such beds 

 occur proved that the small group of buttes in which I first found the 



