Question: Which documentary was released first, The Plow That Broke the Plains or Seal Island?

Context paragraphs:
Duiker Island: Duiker Island or Duikereiland ("Afrikaans"), also known as Seal Island (not to be confused with the nearby Seal Island), is an island off Hout Bay near Cape Town South Africa.  It is 77 by 95 metres in size, with an area of about 0.4 hectare.

West Island Conservation Park: West Island Conservation Park is a protected area occupying both West Island and Seal Island in coastal waters near Victor Harbor in South Australia.  The park was proclaimed in 1972 following the enactment of the "National Parks and Wildlife Act 1972" with the protection initially applying to West Island only which itself previously had reserve status under the "Fauna Conservation Act 1964-1965".  Seal Island was added to the park in 1979.  The purpose of the park is to protect the breeding populations of bird species present on both islands such as little penguins, silver gulls, crested terns, Caspian terns and fairy terns.  The conservation park is classified as an IUCN Category Ia protected area.

Prime Seal Island: Prime Seal Island is a long island, with a high central ridge and an area of 1220 ha, in south-eastern Australia.  It is part of Tasmania’s Prime Seal Island Group, lying in eastern Bass Strait west of Flinders in the Furneaux Group.  Geologically, it is limestone overlying granite and has notable karst features, including caves.  It is leased for farming and is extensively grazed by sheep and cattle as well as the native Tasmanian pademelons.

Seal Island (Nova Scotia): Seal Island (also known as Great Seal Island) is an island on the outermost extreme of Southwestern Nova Scotia, Canada, in the Municipality of the District of Argyle in Yarmouth County.  It is approximately 4.3 km long and 0.8 km wide and is surrounded on its east, south and west sides by dangerous shoals.  It is surrounded by the Atlantic Ocean and is the biggest of a group of five islands which extend north for 12 km .  It is the second southernmost point of land of Nova Scotia.  The southern tip of nearby Cape Sable Island is 250 m farther south than the southern tip of land on Seal Island.

Seal Island, Anguilla: Seal Island is a small island off the northwest coast of Anguilla.  It is located some two kilometres to the west of the Prickly Pear Cays at 18° 16' N, 63° 9' W, and lies at the centre of the Seal island Reef System Marine Park.  The area is popular with scuba divers.

The Plow That Broke the Plains: The Plow That Broke the Plains is a 1936 short documentary film which shows what happened to the Great Plains region of the United States and Canada when uncontrolled agricultural farming led to the Dust Bowl.  It was written and directed by Pare Lorentz.  The film was narrated by the American actor and baritone Thomas Hardie Chalmers.

Seal of Montana: The Great Seal of the State of Montana was adopted in 1865, when Montana was a United States Territory.  When it became a state in 1889, it was decided to use the same seal.  In 1891, proposals were made to make changes or adopt a brand new seal.  None of these proposals passed legislation.  The outer ring of the seal contains the text "The Great Seal of the State of Montana".  The inner circle depicts a landscape of mountains, plains and forests by the Great Falls on the Missouri River.  A plow, a pick and a shovel are depicted on the front, representing the state's industry.  The banner at the bottom of the seal reads the territorial motto of "Oro y Plata", meaning "Gold and Silver" in Spanish.

Althorpe Islands Conservation Park: Althorpe Islands Conservation Park is a protected area in the Australian state of South Australia occupying the Althorpe Islands, Haystack Island and Seal Island in Investigator Strait near the town of Stenhouse Bay.  The conservation park was proclaimed in 1972 following the enactment of the "National Parks and Wildlife Act 1972" with the protection initially applying to the Western Islets in the Althorpe Islands, Haystack Island and Seal Island with Althorpe Island itself was not added until 1997.  The purpose of the conservation park is ‘to protect important wildlife habitat, particularly for sea-bird populations’.  It is classified as an IUCN Category Ia protected area.

Seal Island (film): Seal Island is a 1948 American documentary film directed by James Algar.  Produced by Walt Disney, it was the first installment of the "True-Life Adventures" series of nature documentaries.  It won an Academy Award in 1949 for Best Short Subject (Two-Reel).

Criehaven, Maine: Criehaven is an alternative name for Ragged Island, an unorganized territory in Knox County, Maine, United States.  Criehaven was formerly a plantation including Ragged Island just south of Matinicus Isle in outer Penobscot Bay, plus Matinicus Rock to its southeast, and Seal Island, the location of Seal Island National Wildlife Refuge, to its northeast.  Criehaven surrendered its organization and reverted to an unorganized territory in 1925, but the name persists.

Supporting paragraphs: The Plow That Broke the Plains Seal Island (film)
Answer: The Plow That Broke the Plains