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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1897 Excerpt:...the same causes the main divides are also transverse to the structure and on these for a width of from half a mile to several miles the topography is usually not well enough marked to indicate structure. Many other local and minor causes, such as change in the character of the rocks, faulting, crushing of strata, constant variation in the character of the folds, and others enter as factors to complicate the topography. Though it is probable that the topography, if worked out in detail, would be found to be closely governed by the structure, modified by the factors mentioned, yet, when it is considered that, on account of the density of the forest, it is but rarely that the "lay of the land" can be made out for more than one or two hundred yards from the course pursued, it will be understood why, in a rapid reconnaissance like that undertaken, but little more than suggestions could be obtained from the topography. For these reasons the structure has, in no case, been assumed from the topography alone. Overturns.--Overturns are a common feature of the area. In Fig. 13 is a simple overturn, and 011 the right side (Fig. 14) are shown the corresponding dips of beds at surfaces of different levels as AB, CD, EF, GH. Thus, in the case of A'B' the axis is readily recognized; but remembering that no correlation of beds can be made, the section at that point would naturally be interpreted as an Flgs. 13, 14.--Diagrams illustrating the structures shown by eroding an overturn to different depths. anticline at b and a syncline at a. Such overturns are liable to lead to a confusion which can only be cleared up by careful detailed work. In CD' and E'F', the structure is the same, but is somewhat modified. Most of the overturns found have been eroded so as to giv...