344 PROCEEDINGS OF THE ACADEMY OF [1880. 



of this are numerous. There is now a railroad running straight 

 up the mountain side from the base to the summit. Near the 

 timber line, a cut had to be made through an area covered by 

 mature Balsam Firs. This cut was about 8 or 10 feet deep. 

 Under the trees moss and dead roots and old fir leaves had made 

 an earthy strata of a foot, or in places, more in depth. The moss 

 was still green from the rains, melting snows, and fogs of this 

 elevated res-ion, and sustaining the various kinds of low veoeta- 

 tion common to these alpine heights. Young firs were springing 

 up in great abundance. But all the larger trees were dead, though 

 here and there might be seen a branch with a few lingering green 

 leaves. This mass of dead, standing timber occupied several acres. 

 The reason for their death was evident. The railroad cut showed 

 that the forest stood on a mass of large but loose gneiss rocks, 

 through which the waters from the two thousand feet of loose rock 

 above rushed as soon as the railroad cut was made, carrying with 

 it all the earthy matter on which the larger trees subsisted, but 

 leaving the tough turf}^ matter at the surface, on which smaller 

 trees of the same sort may live for many years, though the larger 

 ones cannot longer exist. With the death of the larger trees 

 there is, of course, an increase of light, and then the Sierochloe, 

 with other grasses and sedges, speedily take possession, holding 

 together the loose soil, and even permitting in many cases an 

 increase of the earthy layer, b}^ holding much of the disintegrated 

 rock which may be washed or blown on from above. Carefully 

 examining patches of scrubby spruces above the timber line, it is 

 not uncommon to find dark patches of vegetable mould evidently 

 the remains of large trees that have been growing where now only 

 the masses of small scrubby plants exist. In some places a sharp 

 stick may be pushed down among the scrubby firs and spruces, 

 and the earth found to be but a foot or so deep over the loose 

 rock below, from which the earth has been wholly washed away. 

 Again, there are some places often nearly an acre in extent where 

 the scrubby firs are still standing, dead, from the earth having 

 been washed away from below upwards, not leaving enough for 

 even the moderate demands of these little bushes. 



In view of the facts detailed we may conclude that at the 

 elevation of these mountain chains, the lowland veafetation was 

 carried up at the same time. The summits, covered by luxuriant 

 forests would present a cooler surface to the moist clouds, and 

 there would be less condensation than on bare sun-warmed rocks, 

 and deep snows would be less frequent, and not suflicient to inter- 

 fere much with arboreal growth. But the rain would of necessity 

 carry down the earth and disintegrated rock to lower levels ; and 

 the melting snows, such as there were, would make this downward 

 progress of the soil continuous. In some mountains where the rock 

 was easily broken by frost, as in Colorado and the White Mountains, 

 it would be very difl!icult for the soil to hold its own against these 

 forces of gravitation ; but on more solid rock the mass of tree 



