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<br />
<br />mile 65, tho rocks dip slightly to the east so that the river again
<br />flows over successively younger formations. , Betwcen,Trinidad and
<br />Alfalfa, the river flows through soft shale plains. From Alfalfa to
<br />within 17 miles of the mouth, th,e stream flows over the hard sandstone
<br />and shale. Narrow canyons arc characteris!,ic of this section except
<br />near Higbee, Colo. (mile 38), where the river has cut entirely through'
<br />the hard sandstones and into the softer Morrison shale, thus widening
<br />the vaIlcy in this vicinity. Throughout the lower 17 miles of its
<br />course, the river again flows through the soft shale plains.
<br />9. Stream 81ope8-Ohannel eapaeitie8.-In the headwater reaches up-
<br />stream from Weston, Colo. (mile 180), gradients are several hundred
<br />feet per mile. Below that point to the vicinity o(Long Can,uyoJl (mile
<br />164), slopes ,are in excess of 50 feet per mile. From Long Canyon to
<br />Alfalfa, the stream bed decreases in elevation at rates of between 50
<br />and 20 feet per mile. In the lower reaches, gradients average about
<br />8.5 feet per mile. Channel capacities do not increase downstream
<br />as the stream meanders in the, flood plain, except through the canYOJl
<br />section, producing variable bank heights and channel widths. River
<br />slopes, channel capacities, and other pertinent data are given iJl
<br />table No.2. A profile of the river is shown on map No.8, I appendix A.
<br />
<br />TABLE No. 2.-Pu1'gatoire River-River slopes and minimum channel capacitie.8
<br />
<br /> "
<br /> Inter- Approxi~ Low- Approxf.
<br /> mateele-
<br /> ;Miles veiling vattOR, water mate cban-
<br />Locullty above miles low water slope, nolcapac-
<br /> mouth by feet above feet ity,cublc
<br /> river' meansoa p" feet'per
<br /> level mile second
<br /> -.
<br />Junction, Nortband Middle Forks.....___________.... 186 7,400
<br /> 22 65.7 (')
<br />Mouth of r..o~g Callyou._____.__._______.__._______h. '6< 6,175
<br /> 7 26,3 16,000
<br />Trinldad_ __h.____._.. ...._._h_____.___.______________ IS? 5,987 15,000
<br /> 35 19.2 15,000
<br />AlCaIra (head of canyon sectlon)mnu_____________._._ 122 , .5,320
<br /> " 14.2 (')
<br />Nine-mile dlllD slte______._____.__..._.__n..___.______ .. 4,240
<br /> 8 ... 20,000
<br />Higbee_ _n_..___...___________._______. _._n._.. .~_..~ 38 4,166
<br /> 21 7.. 86,000
<br />Highland dam slte__..___._____...........__._...._____. 17 ',000
<br /> 17 8,' 25.000
<br />Mouth_ ___"__._____________~----n--__---~--u-------- 0 3,856
<br />
<br />rNot~tlihated.
<br />t Not Hood plain.
<br />
<br />,10. SoiI8.-Four soils groups found in the Purgatoire River drain-
<br />age area vary greatly in character. In the upper or western part of
<br />the area above Stonewall, the Rough Stony, and Alpine Meadow
<br />group are mostl:y: of a complex of barren rough stony land. In the
<br />meadows the soIls are usuaIly shaIlow and stony. From Stonewall
<br />downstream'to the front range below Trinidad, Lithosols cover most of
<br />the area. The dominant types in this group are Underwood,Babb
<br />and McCammon-Deschutes. These soils are complex, as they are
<br />developed on rough terrain from a variety of parent materials. They
<br />,are mostly,sh~llow, ston:J;, and lacking in very' definite profile develop,
<br />ment aJld subject to eroSIOn. The Brown soils are found in the plains
<br />area. These soils are mostly silt loams, though there are also some'
<br />
<br />I This map is not printed.
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