Santa Rosae (also spelled Santarosae) was, before the end of the last ice age, an ancient landmass off the coast of present-day

southern California Southern California (commonly shortened to SoCal) is a geographic and Cultural area, cultural List of regions of California, region that generally comprises the southern portion of the U.S. state of California. Its densely populated coastal reg ...

, near

Santa Barbara County Santa Barbara County, officially the County of Santa Barbara (), is a county located in Southern California. As of the 2020 United States census, the population was 448,229. The county seat is Santa Barbara, and the largest city is Santa M ...

and

Ventura County Ventura County () is a county located in the southern part of the U.S. state of California. As of the 2020 census, the population was 843,843. The largest city is Oxnard, and the county seat is the city of Ventura. Ventura County comprises ...

, of which the northern

Channel Islands of California The Channel Islands () are an eight-island archipelago located within the Southern California Bight in the Pacific Ocean, off the coast of California. They define the Santa Barbara Channel between the islands and the California mainland. The ...

are remnants. At its largest, Santa Rosae was roughly 3-4 times bigger than the northern Channel Islands of today, nearly 125 km (77.67 miles) long from east to west. Between about 20,000 and 5,000 years ago, Santa Rosae lost about 70% of its land mass to post-glacial rising sea level, leaving behind a vast submerged landscape currently being explored by scientists. San Miguel, Santa Rosa, Santa Cruz, and Anacapa Island comprise the unsubmerged portions of Santa Rosae today. This island was about 5 miles offshore. It broke up between about 11,000 and 9,000 years ago, and the present northern Channel Islands took their shape after the continental ice sheets melted and sea levels rose by about 100 meters. There is evidence to suggest that a now-submerged island, Calafia, lay between Santa Rosae and the

mainland Mainland is defined as "relating to or forming the main part of a country or continent, not including the islands around it egardless of status under territorial jurisdiction by an entity" The term is often politically, economically and/or demogr ...

. Santa Rosae had a population of pygmy mammoths (''Mammuthus exilis''), which became extinct roughly 13,000 years ago. On Santa Rosa Island was found the ~13,000-year-old skeleton of Arlington Springs Man, among the oldest human remains yet found in

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

. As Santa Rosae was not connected to the mainland at the time, this shows that

Paleo-indians Paleo-Indians were the first peoples who entered and subsequently inhabited the Americas towards the end of the Late Pleistocene period. The prefix ''paleo-'' comes from . The term ''Paleo-Indians'' applies specifically to the lithic period in ...

settled the island using boats. Archaeological evidence shows that these Paleocoastal peoples had sophisticated maritime technologies and fished, hunted marine mammals and birds, and harvested island plant foods. These Paleocoastal peoples, who survived on the island until about 8,000 years ago, may be the ancestors of the Island

Chumash Chumash may refer to: *Chumash (Judaism), a Hebrew word for the Pentateuch, used in Judaism *Chumash people, a Native American people of southern California *Chumashan languages, Indigenous languages of California See also

* Pentateuch (dis ...

tribe, who lived on the northern Channel Islands for millennia until Spanish authorities removed them to mainland missions in the 1820s.Braje, T.J., J.G. Costello, J.M. Erlandson, M.A. Glassow, J.R. Johnson, D.P. Morris, J.E. Perry, & T.C. Rick. 2010
Channel Islands National Park Archaeological Overview and Assessment
(M. Glassow, editor). National Park Service, digital volume.

References

{{authority control Channel Islands of California Geology of California Pleistocene California Former islands of the United States Geography of Southern California Geology of Santa Barbara County, California Geology of Ventura County, California Islands of California Islands of the Pacific Ocean Natural history of the Channel Islands of California Pleistocene Series of North America Former islands from the last glacial maximum