Interpretation of historic maps and aerial photographs and field work indicate the following extensive erosional changes at point A ±o Nuevo during the past 200 - 300 years: 1. Formation of the channel between the point and island since 1603. 2. Erosional destruction of the broad beach along the north shore that provided sand to the 5000 - 6000 year old dune field, resulting in the disappearance and stabilization of the dune field. 3. Recent (past 30 years) extensive erosion along the south shore of the point, an area where there had been zero erosion during the prior 120 years, or longer. 4. Disappearance of the broad beaches along the south side of the point, beaches that are shown on the 1853 shoreline maps. 5. Extensive erosion along the north shore which has exposed a series of peats ranging in age from 400 to approximately 4000 years in age. Point A ±o Nuevo, a broad low relief headland, is underlain by the 83 ka and 105 ka marine terraces, which overlie varied and complexly faulted (San Gregorio fault zone) bedrock consisting of late Cretaceous and Tertiary sediments. The terrace is overlain by aeolian dunes that have formed along the broad northern windward beach in response to the predominant northwesterly winds. The dunes march slowly across the point only to plunge off the southern cliff and rejoin the littoral drift along the south shore. The narrow uplifted fault block that underlies A ±o Nuevo Island apparently has acted as a trap for littoral drift of sediment for about 5000 to 6000 years, essentially since sea-level rose to near its present level. The creation of the channel between the point and island permanently changed the long term equilibrium in littoral drift. The sand trapped behind the point started to slowly move through the channel adding to the "normal" volume of littoral drift moving along the coastline. Over time the soft terrace sands were also eroded resulting in rapid widening of the channel as indicated by historic maps. As the northern beaches thinned and the channel widened the down drift beaches widened, providing protection to the sea cliffs from wave attack. The mass of sand available to the littoral drift slowly moved south along the coastline eventually reaching northern Monterey Bay. Along beaches protected from the predominant northwest and westerly winter swells beaches widened protecting the late Holocene sea cliffs from wave attack except during the most severe winter storms. This resulted in a 200-300 year period in which northern Monterey Bay beaches have been abnormally wide, protecting the sea cliffs. Consequently since the advent of European settlers in California beaches have been abnormally wide and cliff erosion in many areas negligible. The point source of sand at Point A ±o Nuevo (on the order of 13 to 20 million cubic yards (perhaps more) is now exhausted. Beaches down drift from the point are thinning and sea cliff erosion is accelerating. Major changes in beach width and sea cliff erosion are apparent along the south shore of Point A ±o Nuevo, south of Waddell Creek and at Greyhound Rock. Some thinning of beaches may already be occurring in Northern Monterey Bay. It appears that the disequilibrium period of high volumes of littoral drift and severely reduced sea cliff erosion in Northern Monterey Bay may be ending, and that we are returning to the normal equilibrium that existed for approximately 6000 years prior to the formation of the channel between Point A ±o Nuevo and A ±o Nuevo Island. If correct, this sequence of events also suggests that coastal erosion rates determined from short term (40-60 year) studies may underestimate the long term erosion rates. At a minimum these events suggests should remind us how difficult it is to determine long term rates for geomorphic processes from short term observations. In this instance the short term period of disequilibrium is 200 to 300 years, a long term human time period, but a short term period in geologic time.