THE IRRIGATION AGE. 



939 



has leached from it much if not all of its content of in- 

 jurious salts, as well as much of the mineral matter needed 

 as plant food. For the same reason, in the so-called arid 

 regions, correlated with the liability to become alkaline under 

 careless irrigation is the greater fertility of the land due 

 to the greater abundance of mineral plant food. 



The salts which render soil alkaline are, in the order of 

 their injurious effects, sodium carbonate ("black alkali"), 

 sodium sulphate ("Glauber's salt"), and sodium chloride 

 (common salt). These are originally so widely scattered 

 in small particles through the soil and subsoil as not to 

 be injurious. They are very readily dissolved in the water 

 put on in subirrigation, which penetrates both the soil and 

 the subsoil. As this water is drawn to the surface and 

 evaporated, it leaves these salts behind it on the surface 

 of the ground. As a result of this continuous process, the 

 salts are leached from the soil and subsoil and accumulate 

 on the surface of the soil, rendering it in time unfit for 

 tilling. Once in solution, the only way the salts are rede- 

 posited in the soil is by evaporation. The remedy is of 

 course to reverse the process of irrigation ; that is to say, 

 apply the water at the surface, preferably by flooding, and 

 to withdraw it from below by draining, thus continually 

 carrying away the salts in solution and lessening their 

 amount in the soil. This method, as just pointed out, has 

 the disadvantage of removing from the soil some of its 

 valuable elements. 



Not all of the water conies immediately to the surface 

 to be evaporated, especially on the less gently sloping grav- 

 elly land of the alluvial-fan formations to the west. A 

 portion of the water continues down the slope as underflow- 

 ing ground water until forced to the surface by clay beds 

 beneath. Here it issues as a "seep," usually making an 

 "alkali spot." 



How short-sighted was the man who congratulated him- 

 self because his land required no irrigation when his next 

 neighbor's land above was thoroughly saturated or "subbed." 

 He simply was slowly accumulating a large part of his neigh- 

 bor's alkali. Perhaps his neighbor in turn was having alkali 

 unloaded upon his land. But the man for whom there is no 

 escaping the alkali under the system of subirrigation is 

 the one on whose place the seep rises to the surface. As 

 noted before, the remedy lies in- the surface application of 

 the water, with subsurface drainage, not only greatly lessen- 

 ing the needful amount and making the supply irrigate a 

 larger territory, but carrying away the alkali. 



The report referred to above, based on careful study 

 of the valley, concludes that the amount of alkali in the 

 valley is nowhere so great as to preclude successful reclama- 

 tion by proper methods. 



The East Ranges. 



Commencing north of Poncha Pass, the Sangre de Cristo 

 range forms a true sierra extending southeastward and 

 culminating in the massif of the Sierra Blanca group of 

 peaks. The sky line, formed by a series of pointed peaks 

 with intervals of sharply serrate and jagged crest line, 

 and the precipitous front, rising abruptly from the level 

 plain to the height of a mile, combine to make this range 

 one of the boldest and most majestic in the country. 



The geologic boundaries in this range, as laid down on 

 the Hayden map, are very much at fault. Only the most 

 cursory examination has been made of the range, which 

 has been ascended or crossed by geologists but a few times 

 at most. The formations involved, so far as known, are 

 basal gneiss, schists, and granite ; intrusive granite : quartz 

 conglomerate ; pudding-stone conglomerate and red sand- 

 stone ; and limestone and shales. The ages assigned to these 

 formations by the Hayden geologists are as follows : Gneisses, 

 schists, etc., Archean; pudding-stone conglomerate and red 

 sandstone, upper Carboniferous ; and limestone and shales, 

 lower Carboneriferous. 



Reference has been made to the occurrence of limestones 

 and sandstones in the vicinity of Villa Grove. The outcrops, 

 as laid down on the Hayden map, show lower Carboniferous 

 rocks facing the valley and upper Carboniferous behind and 

 above. The dip is toward the valley, thus indicating an 

 overturn. On the east side of the valley the same distribu- 

 tion of formations is represented, the upper Carboniferous 

 forming the upper flanks of the Sangro de Cristo Range, 

 the lower Carboniferous restricted to two outcrops on the 

 western foot of the range. This stratigraphic arrangement, 



taken in connection with the described anticlinal structure 

 of the range, is altogether improbable. Lee has recently 

 shown for the Culebra Range that the limestones marked 

 on the Hayden map as lower Carboniferous are in reality 

 upper Carboniferous and lie on the basal Archean granite, 

 indicating the entire absense of lower Carboniferous ; and 

 this is probably true for the whole range except the north 

 end near Salida, where lower Carboniferous limestone carry- 

 ing fossils with a strong Devonian facies is known. If 

 the same mistake that was made in the Culebra has been 

 made in regard to the age of the limestone east and west 

 of Villa Grove, the structural difficulty disappears and the 

 range is readily interpreted as a great anticline and the 

 valley as a great syncline, the limestone being younger and 

 overlying the sandstones and conglomerates. 



In the saddle between Baldy and Blanca peaks is a 

 bed of conglomerate which is quite different from the con- 

 glomerate in the north end of the range, in that the pebbles, 

 which rarely exceed 1 or 2 inches in diameter, are all of 

 pure quartz, while the boulders of the Carboniferous con- 

 glomerate are large and are made up of all sorts of igneous 

 rocks. This conglomerate in the gap has a thickness of a 

 hundred feet or so, rests on the granite, and has a very 

 ferruginous sandy matrix, the reddish color showing at a 

 long distance. Down Ute Creek the conglomerate is more 

 pronounced in character, and it lies against the foot of 

 Baldy Peak upon the truncated edges of steeply dipping and 

 intruded crystalline rocks. Its apparent thickness is over 

 100 ft., and the dip is 14 to 16 N. 15 E. It stretches 

 away north of Baldy Peak down the valley of Huerfano 

 river, with a dip of 8 or 10 in a direction north of east. 

 On the north side of the valley the dip of the contact, 

 which from the crumpled condition of the conglomerate 

 seems to be a plane of movement, is 36 in a direction 

 south of east. To the east the dip is more gentle, 20 in 

 the same direction. In the distance down the north side 

 of the valley can be seen bare white patches limestone or 

 light shales. No doubt the upward formations succeeding the 

 conglomerate above would be shown in a section down the 

 ridge in the direction of the dip, and perhaps also the re- 

 lation of the conglomerate to the conglomerates and lime- 

 stones of the northern part of the range and of Veta 

 Pass. These relations not having been ascertained, the age 

 of this conglomerate must remain for the present unde- 

 termined. 



(To Be Continued in July.) 



SOME SEASONABLE SUGGESTIONS. 



The Western Forestry and Conservation Association, 

 composed of the principal timber-owners and lumber mill 

 operators in California, Oregon, Washington, Idaho and Mon- 

 tana, and headed by Judge Albert L. Flewelling of Spokane, 

 has issued a pamphlet regarding the needs and methods of 

 saving life and property from destruction in forest fires, and 

 urging the observance of the following simple rules : 



Don't toss away burning matches or tobacco. 



Don't make a camp fire in leaves, rotten wood or against 

 logs, where it may spread or where you cannot be sure.it is 

 out. 

 . Never leave a fire until it is out. 



Don't burn a slashing in the dry season without a permit 

 and without taking care to keep the fire from spreading. 



Put out any fire you find, if you can ; if you cannot do 

 so, notify a fire warden, some other public officer or the land 

 owner. 



The text of the pamphlet consists of a series of questions 

 and answers, with a view to interesting school children as 

 well as adults in the forest protection movement. 



After showing that the states of Oregon, Washington, 

 California, Idaho and Montana contain more than 50 per 

 cent of all the timber in the Union, E. T. Allen, forester of 

 the association, who compiled the data, says : 



"Next to food itself, no product is so necessary to the 

 human race as wood. People must have it for fuel, for their 

 houses, barns and fences, to build ships and railroads, and 

 for almost every article used by civilized man. Having 

 plenty of it, we not only get all these things cheaper ourselves, 

 but can sell it to other states and countries which have no 

 forests." 



The forests are one of our chief means of support, as 

 lumbering is a great industry. It brings more than $125,000,- 



