Jug Handle State Natural Reserve

About the park

Ecological Staircase Trail
This trail takes the visitor on a tour of the geological updrift from the coast to the Pygmy Forest two and a half mile inland. This marine terrace sequence illustrates a successional story unparalleled elsewhere in California. The composition and processes responsible for this unique ecological setting offer a diverse selection of interpretive opportunities.

Jug Handle State Natural Reserve is a special place. Few places on earth display a more complete record of ecological succession. Each of the five terraces represents one stage in a progression of successional environments. Jug Handle, then, is one of the few opportunities to interpret this aspect of the coastal spectrum of ecological succession and landscape evolution.

The material base from which the terraces were fashioned is composed of a uniform body of graywacke sandstone (Bailey and Erwin 1959). Although each terrace has evolved from the same parent material, each has been weathered for different lengths of time. The soils, plants, and hydrologic associations on each terrace are affected by the degree of change the weathering has produced in the sandstone (Fox 1976 p. 5).

The structure of the terraces at Jug Handle is a result of the movement of the earth's crust (plate tectonics) and the fluctuation of sea level during the Pleistocene. In the last several million years, the continent of North America has moved northwest, and the coastline along the Mendocino coast has risen slowly in relationship to the increase of the sea level brought on by the melting of the continental glaciers. These two factors are massive agents in the shaping of land forms and are rarely seen so clearly outside the desert regions of the world.

The principal sculpturing agent at Jug Handle has been the sea. During periods of the Pleistocene when the glaciers were retreating northward, sea level rose more rapidly than the land was rising. As the pounding waves were uplifted onto the land, they fashioned a smooth underwater terrace. With renewal of glaciation, the waves slowly receded as the sea level fell.

Deposits of gravel and sand (beach material) were spread across the emerging terrace by the retreating waves (Jenny 1973 p. 8). Continued uplifting raised the terrace clear of subsequent rises in sea level. In this fashion, new terraces were created where older ones had existed. Terrace No. 5 (the oldest) was once at the elevation now occupied by No. 4 and so on.

This repetitive sequence proceeded at intervals of approximately 100,000 years and involved about 100 feet of uplift to form each of the terraces. The higher the terrace the older it is, and the longer its beach materials have been subjected to weathering.

Another active agent forming the land at Jug Handle has been the wind. Coastal breezes have been depositing beach material on the first terrace where the bluffs are low. Similarly, in the past the seaward edge of each terrace was covered with dune-building material that is now ancient.