128 



THE OREGON NATURALIST. 



The strike and dip of the rocks vary greatly 

 in short distances, and I could not, in the time 

 I had to give, determine what an average 

 would be in either case. The disintegrating 

 forces of water, frost, air and light, are all 

 beautifully illustrated. The rocks, especially 

 near the summit, have the appearance of 

 great age. I noticed much erratic material, 

 and some large boulders more or less round- 

 ed and worn. There seemed to be few 

 accessory minerals in the rocks. Mica, 

 hornblende, feldspar, and tourmaline were 

 only found in small sized pieces. No beryl 

 was seen. 



Below the half-way house the mountain is 

 heavily timbered, but above that point only 

 a dwarfish growth of arborescent plants re- 

 main; which, in the next mile or two die 

 out and are replaced by a few grasses and 

 cryptogams; the latter represented mostly by 

 lichens and mosses. These are found 

 ]5lentifully all over the top of the mountain, 

 and among them are some interesting species. 

 It is among these boreal plants and moss 

 covered rocks that the very interesting Alpine 

 butterfly {Chionobas semidea) finds its only 

 habitat in New England. The catei pillar 

 feeds upon lichens. The butterfly flies at 

 ordinary elevations in Labrador, and the 

 colony upon Mt. Washington was probably 

 left there in the latter part of the Glacial 

 Period; and, after a time becoming complete- 

 ly isolated from its kind by the recession of 

 the ice to the notthward, has gradually be- 

 come extinct upon other mountain summits, 

 until, af the present time, it finds the 



conditions of environment suitable for con- 

 tinued existence and increase upon this one 

 mountain summit only. As it is a desirable 

 species in many collections, and as collectors 

 are beginning to make large captures of it 

 when possible, it is an open question how 

 long it may be found here. It is pretty 

 certain, however, that it will become extinct 

 on this mountain in the near future, unless 

 protective legislation is secured in its behalf. 

 1 found the species well represented iiy 

 individuals from the 5th mile pi«t to the 

 summit, and was fortunate enough to take 

 nine specimens without a net. The coloration 

 and habits of the butterfly might be taken as 

 a fine illustration oT protective resemblance 

 if it could be shown to have natural enemies 

 that could be effected thereby, other than 

 man. So nearly does its color harmonize 

 with the color of the rocks and lichens upon 

 which it alights, that it requires the sharp 

 eye of the trained entomologist to detect it 

 when not in flight. The butterfly has the 

 habit of rising suddenly from its resting 

 place, flying a few rods more or less, and 

 alighting quickly, much like certain moths; 

 which, indeed, it much resembles in its 

 general characteristics. This is the only 

 species which I observed upon the upper 

 part of the mountain, except a single example 

 of Vanessa Mitbertii, in fine condition, about 

 a mile below the Summit House; which I 

 desired to capture very muc'i, but could not 

 do so without a net. 



(To be continued) 



