International Excursion in America. 
335 
information on the subject of the assimilation of plantations on 
non-forest soil to natural woodland types. To argue from facts of 
the kind mentioned to the startling conclusion that the whole of 
the existing prairies were once forest-covered is, however, scarcely 
legitimate. 
In the near neighbourhood of Lincoln there are areas impreg¬ 
nated with salt, and these bear a specialised vegetation, which, 
according to Professor Clements, shows a well-marked succession 
from saline and brackish aquatic forms through Salicornia commu¬ 
nities to communities of Atriplex, Corispermum, Dondia (Suceda) and 
Salsola. On the less salty portions of this basin, the party met several 
of the typical “ shortgrass ” plants of the Great Plains for the first 
time, such as Bouteloua, Bulbilis and Grindelia. These plants, 
presumably unable to endure the competition of the typical prairie 
species, colonise the edges of the saline areas, where many of the 
prairie plants cannot get enough water, just as they cannot in the 
climatically drier Great Plains. 
In the late afternoon the party had the pleasure of visiting the 
Botanical Department of the University of Nebraska, and of 
listening to a lantern lecture by Dr. Raymond Pool on the sand¬ 
hill vegetation in the north of the state, where there is an immense 
development of inland dunes. Dr. Pool, scarcely recovered from a 
very severe illness, laid the party under a deep obligation by his 
excellent account of this region, of which he has made a thorough 
study. A small example of the same type of vegetation was visited 
on the following day near Yuma, Colorado. 
Lincoln to Akron. 
At six o’clock the party left Lincoln on their westward journey, 
delighted with their reception at the capital of Nebraska. The 
journey to Akron, Colorado, the next stopping-place, a distance of 
a little over 350 miles in a straight line, was made during the night, 
so that the transition between the Prairies and the Great Plains 
was not seen. As one travels westward the altitude gradually rises, 
from 1,148 feet at Lincoln to 4,650 feet at Akron and 5,183 feet at 
Denver, 15 or 20 miles from the foothills of the Rocky Mountains. 
The rainfall gradually decreases, from 27^ inches at Lincoln to 
16 inches at Akron and 14 inches at Denver. These figures, however, 
give little idea of the actual aridity to the inhabitant of a country 
with a maritime climate like that of North-Western Europe, where 
the evaporation rate is very much lower. Most of the country near 
the railroad during the first part of the journey is cultivated, the 
