. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology; Zoology. DAVIS : THE PLATEAU PROVINCE OF UTAH AND ARIZONA. the faults, and the possible continuity of faults across intervals where no break occurs in the topography have therefore an important bearing on the physical history of the region. The following account of certain significant localities on the line of the Sevier-Toroweap fault proceeds from north to south. The Fault at Upper Kanab. — The district that includes the head- waters of the Sevier, the Virgin, and the Kanab, on the Kanab (Utah) Sheet, U. S. Geologic
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology; Zoology. DAVIS : THE PLATEAU PROVINCE OF UTAH AND ARIZONA. the faults, and the possible continuity of faults across intervals where no break occurs in the topography have therefore an important bearing on the physical history of the region. The following account of certain significant localities on the line of the Sevier-Toroweap fault proceeds from north to south. The Fault at Upper Kanab. — The district that includes the head- waters of the Sevier, the Virgin, and the Kanab, on the Kanab (Utah) Sheet, U. S. Geological Survey topographical maps, is of monoclinal structure with gentle eastward dip, in which the Sevier fault, Figure 2, uplifts the eastern half with a heave of nearly one thousand feet (Dutton, a, p. 31). The youngest of the dislocated strata are the Paunsagunt Tertiaries, which are classed as Eocene. Whether the fault occurred early or late in post-Eocene time can be best determined by inquiring iuto the changes effected by general erosion in the topography consequent upon faulting. PAUNSAGUNT. Figure 2. General cross-section at Upper Kanab. The most manifest effects of this fault upon local drainage would have been to produce longitudinal consequent streams in the trough parallel to and somewhat west of the fault line, and short consequent streams flowing west and eastward from the divide, as indicated by the dotted profile of Figure 2. The upper waters of the Sevier and of the Virgin may be in some way related to the inferred longitudinal conse- quent streams west of the fault, but the consequent divide east of the fault is now replaced by the subsequent valley of the Upper Kanab creek, eroded on the weak Cretaceous strata east of the fault and close along the line that should have initially stood at the greatest height. The simplest explanation for such a valley involves two cycles of ero- sion, separated by a regional uplift without significant renewal of fault- ing. Du
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