ABSTRACT
In a region such as the coastal belt of southern California where alluvial plains have been deformed in the latter part of the Pleistocene epoch, the pattern of the consequent streams may be used as a means of determining the positions of some of the underlying geological structures. It is particularly useful in the detection of anticlines. Under favorable conditions the stream pattern is a more accurate means of determining the structure than is the warping of the Pleistocene or Dominguez land surface. Apparently, at the opening of an epoch of deformation the initial warping of the land surface is more closely related to the underlying structure than is the later deformation. Streams entrench themselves as the initial uplift occurs and maintain their pattern by down-cutting throughout later deformation. It is this characteristic of consequent streams which makes them so useful to the structural geologist.
If a sloping area is anticlinally warped the streams on the lower side will be quickened and those on the higher side will not develop at all, or, if they do, the divide will be shifted toward the higher land.
In case an erosion cycle is interrupted by deformation the remnants of the topography and the consequent stream pattern will persist into the later cycle with more or less modification.
