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e e e 3-21 to be developed in tentative form during the preliminary investigation of the site. With the benefit of the additional information obtained during logging and sampling, the original profile is to be refined to include more precise information on the extent, thickness and position in the profile of stratigraphic units. The survey stationing, bank line, and proposed invert level are to be plotted, as are the locations and logs of pits or drill holes. The upper and lower elevations of stratigraphic units will be shown at the appropriate station site. When the correlation of units between pit or drill hole sites has been determined, correlation lines are drawn as shown on Figure 3-4. In this example, it is implied that correlation between test hole sites has been. facilitated by exposures in stream banks. Additional test holes would be required where such exposures are not available. The "U" on the right of the profile test hole location indicates that an undisturbed sample was obtained. A disturbed sample mayor may not be obtained at the same site depending upon whether enough material is available in the undisturbed sample-for classification. The investi- gators have identified this stratigraphic unit as consisting of soil which would resist erosion as a mass rather than as discrete particles. The "D" indicates that a disturbed sample has been obtained. The investigators have made a field determination that the unit is non- coherent and that erosion characteristics are dependent on the indi- vidual particle characteristics. The stratigraphic unit delineations on Figure 3-4 are not dependent on the indicated investigation sites alone but include determinations from observations along stream banks and from hand borings. When the test data have been obtained, results pertinent to the erosion or stability characteristics may be shown or listed on attached report sheets with the data clearly identified with the appropriate units. Ground water, if encountered, should be shown at each of the investigation test hole locations. The longitudinal profile with stratigraphic unit interpretations is primarily for purposes of stability evaluation, and without it the designer does not know that interpretations of soil characteristics have been made between investigation sites. The logs of test pits or drill holes and the plan map showing the location of these investigation sites should accompany the profiles as supporting and supplemental information and a copy will be placed in the design folio. The geologic profile and plan map should show the locations and the extent of outcropping bedrock. They should also show its verified or estimated depth below the present streambed and its relation to the proposed channel invert. Existing erosion or deposition features associated with the outcrop (either up or down stream) should also be shown.