SOIL SURVEY

-162-Table 66 . Frost design soil classification .Percentage,by weight,Typical soil type sFrost finer than under Unified Soi lgroup Kind of soil 0.02 mm Classification Syste mF1 Gravelly soils 3 to 10 GW, GP, GW-GM, GP-G MF2 (a) Gravelly soils 10 to 20 GM, GW-GM, GP-G M(b) Sands 3 to 15 SW, SP, SM, SW-SM, SP-S MF3 (a) Gravelly soils Over 20 GM, G C(b) Sands, except very fine silty sands Over 15 SM, S C(c) Clays, PI> 12CL, C HF4 (a) All silts ML, M H(b) Very fine silty sands Over 15 S M(c) Clays, PI < 12CL, CL-ML(d) Varved clays and other fine-grained, CL, and ML ; CL, ML, and SM ;banded sedimentsCL, CH, and ML ; CL, CH, ML, and SMNote : Taken from the United States Army Corps of Engineers 196 2INTERPRETATION SAssumptions and Considerations which apply to the Interpretations in Table 67 .Ratings of the severity of limitations of the soils of Yoho for variou srecreational uses are shown in Table 67 . These ratings are based on inherent soi lcharacteristics, using guidelines from Table 58 to 64 as they apply to this specifi carea . Essentially the same procedure has been used by Greenlee (1976) in som eProvincial Parks of Alberta, by Knapik and Coen (1974) in the Revelstoke Summi tArea, and by Coen and Holland (1976) in Waterton Lakes National Park . By usin gsuch a system of rating soil limitations, comparisions and extrapolations may b emade within the study area, as well as within the adjacent Mountain National Parks .It should also be noted that the severe limitation class of some authors has been sub -divided into severe and very severe in this study . This was felt to be necessary togive a greater degree of separation among the map units due to the scarcity of map unit swith none to slight limitations .Ratings of the severity of the limitations are shown in Table 67 (only the mos tsevere limitations, and their nature, are specified) . When using these interpretations ,consideration must be given to the following :1 . Interpretations are based on predictions of soil behavior under define dconditions of use and management as specified in the preamble to eac h