Question: Who illustrated the novel in which the fictional location "The Underland" mainly appears?

full_context: Document 1: The Chronicles of Narnia: The Chronicles of Narnia is a series of seven fantasy novels by C. S. Lewis. It is considered a classic of children's literature and is the author's best-known work, having sold over 100 million copies in 47 languages. Written by Lewis, illustrated by Pauline Baynes, and originally published in London between 1950 and 1956, "The Chronicles of Narnia" has been adapted several times, complete or in part, for radio, television, the stage, and film.
Document 2: Lantern Waste: Lantern Waste is a fictional place in "The Chronicles of Narnia" series by C. S. Lewis. It is a wood and is notable as the place where Lucy Pevensie and Mr. Tumnus meet, which is the first scene of Narnia described in the books. The lamppost in the wood is an iconic image of Narnia, and the question of its origin is what convinced Lewis to write more than one book on Narnia. One of King Edmund's titles is "Duke of Lantern Waste".
Document 3: Prince Caspian: Prince Caspian (originally published as Prince Caspian: The Return to Narnia) is a high fantasy novel for children by C. S. Lewis, published by Geoffrey Bles in 1951. It was the second published of seven novels in "The Chronicles of Narnia" (1950–1956), and Lewis had finished writing it in 1949, before the first book was out. It is volume four in recent editions of the series, sequenced according to Narnia history. Like the others, it was illustrated by Pauline Baynes and her work has been retained in many later editions.
Document 4: The Chronicles of Prydain: The Chronicles of Prydain is a pentalogy of children's high fantasy Bildungsroman novels written by American author Lloyd Alexander. Henry Holt published one annually from 1964 to 1968; the second earned a 1966 Newbery Honor and the last won the 1969 Newbery Medal.
Document 5: The Voyage of the Dawn Treader: The Voyage of the Dawn Treader is a high fantasy novel for children by C. S. Lewis, published by Geoffrey Bles in 1952. It was the third published of seven novels in "The Chronicles of Narnia" (1950–1956) and Lewis had finished writing it in 1950, before the first book was out. It is volume five in recent editions, which are sequenced according to Narnia history. Like the others it was illustrated by Pauline Baynes and her work has been retained in many later editions. It is the only Narnia book that does not have a main villain.
Document 6: The Silver Chair: The Silver Chair is a high fantasy novel for children by C. S. Lewis, published by Geoffrey Bles in 1953. It was the fourth published of seven novels in "The Chronicles of Narnia" (1950–1956); it is volume six in recent editions, which are sequenced according to Narnian history. Like the others, it was illustrated by Pauline Baynes and her work has been retained in many later editions.
Document 7: Underland (Narnia): The Underland is a fictional location in the children's fantasy series "The Chronicles of Narnia" by C. S. Lewis. Described by Lewis as lying beneath the land of Narnia, Underland appears mainly in The Silver Chair, where Eustace Scrubb and Jill Pole travel under the ground to reach it in their search for Prince Rilian. They find him in Underland and release him from his enchantment by The Lady of the Green Kirtle.
Document 8: The Kilns: The Kilns, also known as C. S. Lewis House, is the house on the outskirts of Headington Quarry (where Lewis is buried at Holy Trinity Church) in the village of Risinghurst, Oxford, England, where the author C. S. Lewis wrote all of his Narnia books and other classics. The house itself was featured in the Narnia books. Lewis's gardener at The Kilns, Fred Paxford, is said to have inspired the character of Puddleglum the Marshwiggle in "The Silver Chair".
Document 9: Narnia (world): Narnia is a fantasy world created by C. S. Lewis as the primary location for his series of seven fantasy novels for children, "The Chronicles of Narnia". The world is so called after the country of Narnia, in which much of the action of the Chronicles takes place.
Document 10: The Chronicles of Narnia: The Silver Chair: The Chronicles of Narnia: The Silver Chair is an upcoming fantasy adventure film based on "The Silver Chair", the fourth novel published in C. S. Lewis's epic fantasy series "The Chronicles of Narnia" (and sixth in internal chronological order). It is intended to be the fourth installment in "The Chronicles of Narnia" film series, and the first film in the series to be produced by C. S. Lewis Company. This will be the first film in the series to be distributed by TriStar Pictures and Entertainment One and the first not to have the involvement of Walden Media. The film's release date has yet to be announced.
Document 11: Eustace Scrubb: Eustace Clarence Scrubb is a fictional character in C. S. Lewis's Chronicles of Narnia. He appears in "The Voyage of the Dawn Treader", "The Silver Chair", and "The Last Battle". In "The Voyage of the Dawn Treader", he is accompanied by Edmund and Lucy Pevensie, his cousins. In "The Silver Chair" and "The Last Battle", he is accompanied by Jill Pole, a classmate from his school.
Document 12: Aslan's Country: Aslan's Country is a fictional location from C. S. Lewis' "The Chronicles of Narnia" series. It is the home of Aslan, the great lion. It is described as a series of mountains, thousands of feet high, but without snow or ice. Instead, Aslan's Country has a clear blue sky, lush green grass, colourful birds, and beautiful trees. There are entrances to Aslan's Country from all worlds, including Narnia and Earth. It is located beyond Narnia's rising sun at the eastern edge of the world, and indeed rings around the whole Narnian world.
Document 13: Lady of the Green Kirtle: The Lady of the Green Kirtle, also called Queen of Underland and Queen of the Deep Realm, is the main antagonist in "The Silver Chair" by C. S. Lewis. She is sometimes called briefly the "Green Lady" (on analogy with Jadis, the "White Lady"), and she is known also as the "Emerald Witch"; neither name, however, appears in Lewis's text. She enslaved Prince Rilian of Narnia and a horde of gnomes by her witchcraft, and planned to use them to take over Narnia. She is foiled by three friends of Aslan: Eustace Scrubb, Jill Pole, and Puddleglum.
Document 14: Narnia (disambiguation): "The Chronicles of Narnia" are a series of fantasy novels by C. S. (Clive Staples) Lewis, based on which are:
Document 15: The Lion, the Witch and the Wardrobe: The Lion, the Witch and the Wardrobe is a fantasy novel for children by C. S. Lewis, published by Geoffrey Bles in 1950. It is the first published and best known of seven novels in "The Chronicles of Narnia" (1950–1956). Among all the author's books it is also the most widely held in libraries. Although it was written as well as published first in the series, it is volume two in recent editions, which are sequenced by the stories' chronology (the first being "The Magician's Nephew"). Like the others, it was illustrated by Pauline Baynes, and her work has been retained in many later editions.
ground_truth: Pauline Baynes