248 Geological survey of the teeeitoeies. 



worked, yielding readily to the spade or the plow. Excavation is re- 

 markably easy, and no pick or mattock is thought of for such purposes. 

 It might be expected that such a soil readily yielded to atmospheric in- 

 fluences, but such is not the case. Wells in this deposit are frequently 

 walled up only to a point above the water-line ; and on the remainder 

 the spade marks will be visible for years. Indeed, the traveler over 

 Nebraska will often be surprised to see spade-marks and carved-out 

 names and dates years after they were first made, where ordinary soils 

 would soon have fallen away to a gentle slope. This peculiarity of the 

 soil has often been a God-send to poor emigrants. Such often cut out of 

 the hillsides a shelter for themselves and their stock. Many a time 

 when caught out on the roads in a storm, far away from the towns, have 

 I found shelter in a "dug-out" with an emigrant's family, where, cozy 

 and warm, there was perfect comfort, with little expenditure of fuel on 

 the coldest days. In summer such shelters are much cooler than frame 

 or brick houses. I shall never forget one occasion in 1866, when be- 

 wildered by a blinding snow-storm I came to a "dug-out," and although, 

 all the chambers were carved out of the soil (Loess) they were perfectly 

 dry. The wails were hidden and ornamented with Harper's Weekly, 

 with the emanations of Nast's genius made to occupy the conspicuous 

 corners. My hostess, whose cultivated intellect and kindly nature 

 made even this abode a charming resort , was a graduate of an eastern 

 seminary. Her husband, after a failure in business in New York, came 

 here to commence life anew on a homestead by stock-raising. To get a 

 start with young stock no money could be spared for a house. Eight 

 years afterward I found the same family financially independent and 

 living in a beautiful brick mansion, but I doubt whether they had any 

 more substantial happiness than when they were looking for better days 

 in the old temporary "dug-out." Thousands who are still coming into 

 this land of promise are still doing the same thing. So firmly does the 

 material of this deposit stand that after excavations are made in it, un- 

 der-ground passages without number could be constructed without meet- 

 ing any obstacles and without requiring any protection from walls and 

 timber. 



Cause of these peculiarities. 



These peculiarities of the Loess deposits are chiefly owing to the fact 

 that the carbonate of lime has entered into slight chemical combination 

 with the finely comminuted silica. There is always more or less carbonic 

 acid in the atmosphere which is brought down by the rains, and this 

 dissolves the carbonate of lime, which then readily unites with silica, but 

 only to a slight extent, and not enough to destroy its porosity. Though 

 much of the silica is microscopically minute, it has largely preserved its 

 angular structure, and this of course aids the slight chemical union that 

 takes place between it and the carbonate of lime. Had there been more 

 lime and iron in this deposit, and had it been subjected to greater and 

 longer pressure from superincumbent waters, instead of a slightly chemi- 

 cally compacted soil it would have resulted in a sandstone formation 

 incapable of cultivation. There is not enough clayey matter present to 

 prevent the water from percolating through it as perfectly as through 

 sand, though a great deal more slowly. This same peculiarity causes 

 ponds and stagnant water to be rare within the limits of this deposit. 

 Where they do exist in slight depressions on the level plain, it is found 

 that an exceptionally large quantity of clayey matter has been accumu- 

 lated in the soil on the bottom. In Clay, Fillmore, York, and a few other 

 counties there are considerable numbers of ponds, covering from a few 

 acres to half a section of land, grown up around the border with reeds 



