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Chanslor Guest Ranch
Distance: 7.5 Mi2660 N Highway 1
94923-9720 Bodega Bay -
Russian River Getaways
Distance: 7.2 Mi14070 Mill St
95446-8304 Guerneville -
D & G Equity Management
Distance: 7.2 Mi14080 Mill Street
95446 Guerneville -
Guerneville's Visitor
Distance: 8.5 Mi14880 River Rd
95446-9279 Guerneville -
Coastal Vistas
Distance: 13.5 MiPO BOX 413
94923-0413 Bodega Bay
Description
125 million years ago the area now known as Sonoma County was a part of the sea floor. At times this floor was covered by many thousands of feet of water teeming with all varieties of marine life. This sea floor continually received sediments from neighboring lands to the east; all the while, at depths of several miles, vast masses of molten magma slowly migrated upward to solidify as crystalline rock.12 million years ago forces deep within the earth began forming what are now the mountains of northwestern California. These forces brought the ocean floor above sea level and exposed the sediments to wind and rain, where erosion shaped mountains and valleys. The topography was one of low, rolling hills with many lakes occupying valley areas. Two million years ago volcanic activity broke out to the east. Many volcanic vents and cinder cones spewed out volumes of lava and ash as eruption after eruption took place. By the close of this activity, a broad volcanic highland had been formed along what is now the eastern boundary of the county. To the northwest, near what is now the town of Annapolis, there was a long, low, northwesterly-trending valley which was slowly being filled with soft, sandy sediments. Similar materials also were being deposited farther south on the plains which sloped gently from the volcanic highlands to the sea.Once again, mountain building forces came into play, and the long valley near Annapolis was slowly elevated until only its remnants are seen today along the ridge tops. Meanwhile to the south, geologic forces were shaping Sonoma\ and Kenwood Valleys. To the west, however, were still rolling hills, and no evidence of the Santa Rosa Plain could be seen. About one million years ago, during the Pleistocene Epoch, a syncline began to develop west of Sonoma and Kenwood Valleys. Continued arching of the sediments eventually created the Santa Rosa Plain. Toward the close of this epoch, sea level stood about 300 feet (91 meters) lower than it does today because of the vast volumes of water locked in the glaciers of the great ice ages. Drainage from the Santa Rosa Plain originally flowed south toward San Pablo Bay, but uplift near Penngrove blocked this southward drainage. Subsequently, drainage turned toward the Russian River, which continues to carve a westward course across the Coast Ranges.