. Bulletin of the Geological Society of America. Geology. Figure 6.— View of Tepee Butte. Drawn from photograph. age, laying bare the shale. The soft rock thus exposed is being degraded so rapidly that the degradation of the cores can keep pace with it only. Figure 7.—Ideal Section of Butte represented in Figure 6. by the aid of high declivity. The equilibrium of attack and resistance thus maintains high declivity at and near the cores. CONDITIONS AFFECTING FORM AND SIZE. Examination of the butte summits shows that the limestone is dis- integrated primarily by fracture, and the cause is doubtl
. Bulletin of the Geological Society of America. Geology. Figure 6.— View of Tepee Butte. Drawn from photograph. age, laying bare the shale. The soft rock thus exposed is being degraded so rapidly that the degradation of the cores can keep pace with it only. Figure 7.—Ideal Section of Butte represented in Figure 6. by the aid of high declivity. The equilibrium of attack and resistance thus maintains high declivity at and near the cores. CONDITIONS AFFECTING FORM AND SIZE. Examination of the butte summits shows that the limestone is dis- integrated primarily by fracture, and the cause is doubtless found in changes of temperature, including frost. The exposed top of the core is usually shattered and large fragments lie on adjacent slopes. Lower down are progressively smaller fragments, and the external part of the conical mass is evidently a talus of limestone and shale debris. Beneath and protected by this is a conical annulus of undisturbed shale surround- ing the core (see figure 7), but it is probable that the form of the butte depends almost exclusively on factors affecting the disintegration and transportation of the limestone debris. Among these must be reckoned frost, heating and cooling, wetting and drying, rain-beating, wind erosion, solution, burrowing and the mechanical and chemical action of roots. Unless some one factor can be shown to dominate the rest, it will be a matter of great difficulty to analyze the process by which the concave XLVIII—Bull. Geol. Soc. Vol. 6, Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Geological Society of America. [New York : The Society]
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