Question: Which expedition was the man who developed the Chinook dogsled breed part of?

Context paragraphs:
Chinook (dog): The Chinook is a rare breed of sled dog, developed in the state of New Hampshire during the early 20th century.  The Chinook is New Hampshire's official state dog.

Oates Coast: Oates Coast ( ) is that portion of the coast of Antarctica between Cape Hudson and Cape Williams.  It forms the coast of Oates Land, part of the Australian claim to the Antarctic.  The eastern portion of this coast was discovered in February 1911 by Lieutenant Harry Pennell, Royal Navy, commander of the expedition ship "Terra Nova" during the British Antarctic Expedition, 1910–13.  He named the coast after Captain Lawrence E.G. Oates who, with Captain Robert F. Scott and three British Antarctic Expedition companions, perished on the return journey from the South Pole in 1912.  Captain Oates' death was described by Robert Falcon Scott as "the act of a brave man and English gentleman".  The western portion of the coast, the vicinity of the Mawson Peninsula, was first delineated from air photos taken by U.S. Navy Operation Highjump, 1946–47.

Arthur Treadwell Walden: Arthur Treadwell Walden (May 10, 1871 – March 26, 1947) was a Klondike Gold Rush adventurer, dog driver and participant in the first Byrd Antarctic Expedition.  He is also known as an author and developer of the Chinook sled dog breed.

German Shepherd: The German Shepherd (German: Deutscher Schäferhund , ] ) is a breed of medium to large-sized working dog that originated in Germany.  The breed's officially recognized name is German Shepherd Dog in the English language (sometimes abbreviated as "GSD").  The breed is also known as the Alsatian in Britain and Ireland.  The German Shepherd is a relatively new breed of dog, with their origin dating to 1899.  As part of the Herding Group, German Shepherds are working dogs developed originally for herding sheep.  Since that time however, because of their strength, intelligence, trainability, and obedience, German Shepherds around the world are often the preferred breed for many types of work, including disability assistance, search-and-rescue, police and military roles, and even acting.  The German Shepherd is the second-most registered breed by the American Kennel Club and fourth-most registered breed by The Kennel Club in the United Kingdom.

Chinook Point: Chinook Point is a headland in Pacific County, Washington.  Located just northwest of the mouth of the Columbia River, it is historically significant for several reasons.  Captain Robert Gray, the first non-native to enter the river, saw it from Chinook Point in 1792.  In 1805, it was the site of an encampment by the Lewis and Clark Expedition.  It has been the site of military fortifications since 1864, most notably in the late 1890s, when most of the presently surviving Fort Columbia structures were built.  The point, which constitutes the most developed portion of Fort Columbia State Park, was designated a National Historic Landmark in 1961.

Norman D. Vaughan: Colonel Norman Dane Vaughan (December 19, 1905 – December 23, 2005) was an American dogsled driver and explorer whose first claim to fame was participating in Admiral Byrd's first expedition to the South Pole.  He also ran dog teams in a professional capacity as part of a search and rescue unit in World War II, in sporting events like the Olympics and the Iditarod Trail Sled Dog Race, and in three Presidential Inauguration ceremonies.

Jutland horse: The Jutland horse (Danish: "Den jyske hest" ) is a draft horse breed originating in Denmark, named after the Jutland Peninsula which forms the western part of the country.  Usually chestnut, they are a compact, muscular breed known for their calm and willing temperament.  The breed was originally developed for use in agriculture, but today is more often seen in urban settings and at horse shows.  Some of the best known members of the breed pull beer wagons for the Carlsberg brewery around Copenhagen, as well as at competitions and for demonstrations.  Images from the 9th century show a horse similar to the Jutland being used by Viking raiders in what is now Great Britain.  The first written record is from the 12th century, when they were popular as war horses.  Some infusion of bloodlines from other breeds occurred in the 18th century, but the modern Jutland type only began about 1850 with the addition of blood from several other breeds, mainly draft horses.  A stud book was created in the late 19th century, and the Jutland population grew to a maximum of around 15,000 by 1950.  Numbers subsequently declined, and as of 2011 it is estimated that there are only about 1,000 horses remaining.

Skamokawa Valley, Washington: Skamokawa Valley is a census-designated place (CDP) in Wahkiakum County, Washington, north of the town of Cathlamet.  The population was 401 as of the 2010 census.  The CDP includes the Sleepy Hollow community.  The Skamokawa Valley community is part of the Wahkiakum School District, a K-12 school district of about 430 students.  The name of the CDP comes from that of the Wahkiakum Chief Skamokawa who met with Meriwether Lewis and William Clark while their expedition spent the winter of 1805-06 at Fort Clatsop.  His name, Skamokawa, is a Chinook word meaning “smoke over the water,” a reference to the area's foggy climate.

Tipsoo Lake Comfort Station: The Tipsoo Lake Comfort Station was designed by the National Park Service Branch of Plans and Designs in the National Park Service Rustic style and built in Mount Rainier National Park by the Civilian Conservation Corps in 1934.  The design was supervised by Park Service Chief Architect Thomas Chalmers Vint, and is similar to the Sunrise Comfort Station in the central portion of the park.  Located near the park's northern entrance, two comfort station were planned to be part of a developed area in the vicinity of Tipsoo and Chinook Pass, which was never developed beyond the toilet facilities and an entrance arch.  One of these survives and remains in use.  The public toilet facility features rough stonework to window sill level, with a framed wall above and a log-framed roof with cedar shingles.

Cymric cat: The Cymric ( or ) is a breed of domestic cat.  Some cat registries consider the Cymric simply a semi-long-haired variety of the Manx breed, rather than a separate breed.  Except for the length of fur, in all other respects the two varieties are the same, and kittens of either sort may appear in the same litter.  The name comes from "Cymru" (] ), the indigenous Welsh name of Wales, though the breed is not associated with Wales, and the name was possibly given as an attempt to provide a "Celtic"-sounding name for the breed.  The breed's Manx bloodline originated in the Isle of Man, though Canada claims to have developed the long-haired variant.  The breed is called the Longhair Manx or a similar name by some registries.

Supporting paragraphs: Arthur Treadwell Walden Chinook (dog)
Answer: Byrd Antarctic Expedition