1880.] natural sciences of philadelphia. 341 



September 7. 



Dr. R. S. Kenderdine, in the chair. 



Fifteen persons present. 



On large Sphene from Canada. — Dr. A. E. Foote recorded the 

 occurrence of crystals of sphene of unusual size in the county of 

 Renfrew, Canada, near tlie upper part of the navigable portion of 

 the Ottawa River. The largest crystal collected weighed 23^ 

 pounds or raorcthan twenty times as much as the largest liereto- 

 fore found. 



September 14. 

 The President, Dr. Ruschenberoer, in the chair. 

 Twenty-eight persons present. 

 The death of Prof. S. S. Haldeman, a member, was announced. 



On the Timber Line of High Mountains. — Mr. Meehan re- 

 marked that on the tops of most high mountains we find a total 

 absence of ligneous plants. The highest alpine vegetation con- 

 sists for the most part of acaulescent perennials. Lower down 

 we may find some woody species, and often we come to dwarfed 

 forms of trees of species, which, still lower down, form forests of 

 considerable height, and which as timber trees make what is 

 known to mountain travelers as the ''Timber Line." Thus in the 

 mountains of Colorado, the forests commence at about 1000 feet 

 above the sea level, and continue up to about 11,000 feet, where 

 they suddenly cease, and form at that elevation what is there known 

 as the " Timber Line." On Gray's Peak he found Pinus aristata, 

 Pinus Jlexilis, Abies concoJor, and Abies Engelmannii, with 

 some willows forming the timber line. The Coniferous trees 

 were probably 30 or 40 feet high, and it was interesting to 

 note that this tall timber as suddenly ceased, as if a wood had 

 been cut half awaj' bj^ a woodman's axe. But at once commencing 

 where the tall timber ceased, the same species exist as dwarf 

 stunted shrubs seldom exceeding 3 or 4 feet in height, and often 

 but a foot, though trailing widel}' over the groinid. In tiiis 

 stunted condition the species would often extend some fifreen 

 hundred feet higher up, or half way from the recognized timber 

 line to the top of the mountain. Other observers have noted 

 that the average of 11,000 feet marks the entire timber line of 

 the Rocky mountain range. 



So far as he knew this peculiar timber line has been referred 

 wholly to climatic conditions, of which temperature and moisture 



