"An elbow of sand; all beach without a background . . . they have to plant weeds there, they don't grow naturally . . ." (This is an exaggeration, because sheep were grazed extensively on the island at the time).
"That pieces of wood in Nantucket are carried about like bits of the true cross in Rome . . ." (Melville has a point here -- forests on Nantucket, if there were such, were used up by the mid-nineteenth century. Wooden houses were moved around, disassembled, reassembled, packed aboard the decks of ships, carried to California in the Gold Rush. Many wooden houses built in the 1700's not only survive, but are occupied in Nantucket to this day).
"That they are so shut up, belted about, every way inclosed, surrounded, and made an utter island of by the ocean, that etc., etc. etc." (Nantucket was not so isolated then, as Melville surely knows, but he chooses to portray it so for dramatic effect. Indeed, New England seacoast towns, islands included, were more easily accessible then by boat than were the truly isolated inland places, reachable only by very poor dirt roads that were rendered impassable by weather conditions. It is said that housewives on Nantucket had more house furnishings made in Canton, China than made in Boston!)
"But these extravaganzas only show that Nantucket is no Illinois." (Truth be told, in the 1840's, prior to the publication of Moby-Dick, there were probably more millionaires living on Main Street, Nantucket Town, than in the entire state of Illinois. A whaleship full of oil from Sperm whales could net its owner millions in profits. By 1850, the mansions of the whaleship owners, captains, mates, and business people in the whale oil trade rivalled those of New Bedford, extolled in an earlier chapter.)
"What wonder, then, that these Nantucketers, born on a beach, should take to the sea for a livelihood! That at last, launching a navy of great ships on the sea, explored the watery world, and in all seasons and in all oceans declared everlasting war with the mightiest animated mass that has survived the flood." No argument here.
"And thus have these naked Nantucketers, these sea-hermits, issuing from their ant-hill in the sea, overrun and conquered the watery world. Two thirds of this terraqueous globe are the Nantucketer's. For the sea is his. He alone in Bible language goes down to it in ships. There is his home; there lies his business. So at nightfall, the Nantucketer, out of sight of land, furls his sails, and lays him to rest, while under his very pillow rush herds of walruses and whales."
Nantucket's days as premier whaling port of the world were over when this was written.