1889.] NEW YORK ACADEMY OF SCIENCES. 81 



lum, Gray, Helianthus MaximiUani, Schrader, and Parietaria 

 debilis, Forst., are among the most characteristic of this diverse 

 flora. Of these, the last six may be mentioned as becoming 

 more common as we descend, and being really plants of the 

 lower districts. Upon the rocky margins of these canyons, in 

 localities especially exposed to the sweeping storms, occurs the 

 peculiar Spircea ccespitosa, Nutt. — a stout shrub, with stem often 

 an inch and a half in diameter, yet its uppermost portions are 

 rarely more than an inch and a half above the rocks on which it 

 lies closely prostrate. In its company are usually some shrubby 

 Eriogonums, notably^, deflextim, Torr., E. microthemim, Nutt., 

 and E. jlavum, Nutt. 



Continuing our descent of such a canyon until it emerges 

 from the forest, there is an open, but usually grassy plain of 

 greater or less width to traverse, and we stand upon the jagged 

 edge of the plateaus, and gaze into some basin from one to two 

 thousand feet deep, and out across the desert plains which con- 

 stitute the third region of which I have spoken. At nearly all 

 points upon the edge of this plateau, we find such an abrupt 

 descent. Its passage is rendered still more laborious by the 

 dense tangle of scrub oaks which cover it towards the summit. 

 A consideration of the interesting flora of this lower region 

 forms no part of the present paper. 



On the explorations conducted in this forest in 1883, I was 

 accompanied by Mr. Randall Spaulding, to whose exceptional 

 skill in photography we are indebted for the series of views with 

 which my paper has been illustrated, and by Mr. Charles M. 

 Davis and my brother, Mr. Wm. S. Eusby. Through their 

 keen eyesight my list has been enriched with many of its species. 



The subject was further discussed by the President, who 

 referred to his own travels in the same region some years before. 

 He described a severe snow-storm on the table-land, with a fall 

 of eight inches in depth, gave reminiscences of bear-hunting in 

 the forests, and alluded to the cliff dwellings in the San Juan 

 valley, and the remarkable and interesting scenery produced by 

 the abundant growth, in many of the valleys, of yuccas, cacti, 

 and century-plants. 



