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 region that generally comprises the southern portion of the U.S. state of California. It includes the Los Angeles metropolitan area, the second most po ...

, near

Santa Barbara County Santa Barbara County, California, officially the County of Santa Barbara, is located in Southern California. As of the 2020 census, the population was 448,229. The county seat is Santa Barbara, and the largest city is Santa Maria. Santa Barba ...

and

Ventura County Ventura County () is a county 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 the Oxnar ...

, 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. The four Northern Channel Islands are part of the Transverse Ranges geologic province, and ...

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 Rosa is the Italian, Portuguese and Spanish name for Saint Rose. Santa Rosa may also refer to: Places Argentina *Santa Rosa, Mendoza, a city * Santa Rosa, Tinogasta, Catamarca * Santa Rosa, Valle Viejo, Catamarca *Santa Rosa, La Pampa * Sa ...

, Santa Cruz, and

Anacapa Island Anacapa Island (Chumash: ''Anyapax'', meaning "mirage, illusion") is a small volcanic island located about off the coast of Port Hueneme, California, in Ventura County. The island is composed of a series of narrow islets long, oriented ge ...

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 dem ...

. Santa Rosae had a population of

pygmy mammoth The pygmy mammoth or Channel Islands mammoth (''Mammuthus exilis'') is an extinct species of dwarf elephant descended from the Columbian mammoth (''M. columbi'') of mainland North America. This species became extinct during the Quaternary extin ...

s (''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 The Arlington Springs man is a set of Late Pleistocene human remains discovered in 1959 on Santa Rosa Island, one of the Channel Islands located off the coast of Southern California. The Arlington Springs archeological site is protected within no ...

, among the oldest human remains yet found in

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

. As Santa Rosae was not connected to the mainland at the time, this shows that Paleo-indians 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 * Chumash traditional ...

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