The observations set forth in this paper are believed to indicate that:

  1. The northeastern part at least of the San Francisco-Marin Block formerly stood higher instead of lower, as at present, than the southwestern part of the Berkeley Hills Block; a northeastward-facing fault scarp, instead of one sloping southwest, presumably rose along the approximate site of the present hill front. This means a rather striking reversal of the physiographic and drainage conditions now existing in the Eastbay region.

  2. Reversal in direction of the vertical-component movement along the Haywards fault zone occurred, giving rise to the present topographic relations. This movement was in part warping.

  3. The latest movement has been an essentially horizontal northwestward displacement, relatively, of the San Francisco-Marin Block with reference to the Berkeley Hills Block, by at least 1,400 feet.

The late relative movements of the former block with reference to the latter have therefore been successively upward vertically or obliquely, downward vertically or obliquely, horizontally northwestward.

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