286 TRANS. OP THE ACAD. OF SCIENCE. 



Boulder City. 5,536 



Golden City 5,882 



Golden Gate 6,226 



Mount Vernon 6,479 



3. Eastern Slope of Mountains, upper Plateau. 



Central City 8,300 



Survey Station, No. 50, \\ miles above Empire City 8,739 



Gold Hill 8,636 



Osborn's Lake 8,821 



Camp on last Grassy Park towards Mount Audubon 9,346 



4. Timber Line. 



Mount Audubon, eastern slope 11,325 



Long's Peak, northwestern slope 10,800 



5. Peaks. 



Mount Audubon, west of Long's Peak 13,402 



Velie's Peak, north northwest of Long's Peak 13,456 



Long's Peak, approximately 14,056 



It now appears, that the vague estimates of the elevation 

 of Long's Peak were erroneous, and that in altitude it re- 

 mains behind Gray's Peak, Torrey's Peak, and Pike's Peak; 

 while Dr. Parry found that in ruggedness and inaccessibil- 

 ity it exceeded any of them. The expectation that any 

 mountain in Colorado would reach beyond the highest 

 points of the California mountains has not been verified ; 

 on the contrary, several points in the southern part of the 

 Sierra Nevada have been measured last summer (1864), and 

 found to exceed 15,000 feet. (See Preliminary Report in 

 the American Journal of Arts and Sciences for January, 

 1865, p. 10.) 



The elevations of the timber line in the Rocky Mountains 

 have thus far been found to reach, going from south to 

 north : 



FEET. 



On Pike's Peak 12,000 



On Snowy Range- 11,700 to 1 1,800 



On Mount Audubon 11.300 



On Long's Peak 10,800 



On Wind River Mountains 10,160 



The abnormally low elevation of the timber line on Long's 

 Peak, Dr. Parry ascribes to the more bleak and exposed situ- 

 ation of the northwestern slope of those mountains. 



In connection with my former article on the altitudes in 

 the Rocky Mountains, I wish to state, that Prof. Jules 

 Marcou informs me that the top of the Sandia Mountains, in 

 New Mexico, is bare of timber for about sixty feet. 



Before the word "feet" in the first line of page 130, 

 " 2,20u" has been left out. In tropical and sub-tropical 

 climates the snow line is only reached at 5,000 to 6,000 

 feet above the timber line ; in the Alps, the difference 

 between them is but 2,600 feet; and it is not probable 

 that in the Rocky Mountains it would be less than at lc:ist 

 3,000 to 4,000 feet; so that the top of the Wind River 

 Mountains would probably not reach the real snow line. 



