668 



Harshberger: Plant formations of Nockamixox Rocks 



Formation 



The escarpment is precipitous in most places along the entire 



Som 



front of the Nockamlxon Rocks (figures 2, 3, 4, and 5). 

 the cliffs rise as a sheer wall for a distance of 300 feet above the 

 country road at their base. The face of the precipice is irregular 

 owing to the numerous clefts, pockets and shelves, or platforms 

 which are found at various elevations and in various positions and 



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■ 



exposures (figures 4 and 5). The pockets are formed by the 

 falling of masses of rock. The shelves are flat ledges running 



along the face of the precipice (figure 5). One such shelf runs 

 at least two thousand feet in an upward s.loping direction toward 

 the west. In places, it is ten feet wide, in' other places it narrows 

 down to a width of one or two feet. The smaller ledges are 

 occupied by grasses and other herbaceous plants, while the larger 

 projecting flats accommodate various trees, shrubs, and lianes which 

 climb up the vertical rock surfaces. 



Vegetation of larger rock shelv^es : The vegetation of the 

 long shelf just mentioned consists of such trees as Ostrya %nrginianay 



Celtis occidentalis. 



Jiniip 



cr 



/^ 



Ha ma 



'pus op 



Other shrubs are associated with the trees and the nine-bark, viz., 

 Rubns Occident alis (in sunny exposures), Riibiis odoratus^ Taxus 

 canadensis (in dense masses), Staphylea trifolia, Sa^nbiictis race- 



Caprifoli 



Dryopte^ 



Impaiicns fidva (Z biflom\ Smilacina racemosa, Hepatica triloba^ 

 and Aquikgia canadensis. The unshaded rock exposures are 

 characterized by Pentstemon hirsntns {P. pub€scens\ Hciichera 

 amcricana, Achillea Millefolium, Linaria vulgaris, Verbascum 

 ipsus, Cerastinm an^ense var. oblongifoliuvi, Aqtdlegia ca^ia- 



densis^ 

 Cataria. 



West 



ifraga virgi'niensis^ and Nepeta 



5 



masses on the 



an association of plants. Phlox subulata gr 



bare shale rock, while the broad rock shelves here are occupied 



