The gravel-pit is very large and wide, with grass growing round the edges at the top, and dry stringy wildflowers, purple and yellow. It is like a giant's washbowl. And there are mounds of gravel, and holes in the sides of the bowl where gravel has been taken out, and high up in the steep sides there are the little holes that are the little front doors of the little bank-martins' little houses. The children built a castle, of course, but castle-building is rather poor fun when you have no hope of the swishing tide ever coming in to fill up the moat and wash away the drawbridge, and, at the happy last, to wet everybody up to the waist at least. Cyril wanted to dig out a cave to play smugglers in, but the others thought it might bury them alive, so it ended in all spades going to work to dig a hole through the castle to Australia. These children, you see, believed that the world was round, and that on the other side the little Australian boys and girls were really walking wrong way up, like flies on the ceiling, with their heads hanging down into the air. The children dug and they dug and they dug, and their hands got sandy and hot and red, and their faces got damp and shiny. The Lamb had tried to eat the sand, and had cried so hard when he found that it was not, as he had supposed, brown sugar, that he was now tired out, and was lying asleep in a warm fat bunch in the middle of the half-finished castle. This left his brothers and sisters free to work really hard, and the hole that was to come out in Australia soon grew so deep that Jane, who was called Pussy for short, begged the others to stop. "Suppose the bottom of the hole gave way suddenly," said she, "and you tumbled out among the little Australians, all the sand would get in their eyes." "Yes," said Robert; "and they would hate us, and throw stones at us, and not let us see the kangaroos, or opossums, or bluegums, or Emu Brand birds, or anything." Cyril and Anthea knew that Australia was not quite so near as all that, but they agreed to stop using the spades and to go on with their hands. This was quite easy, because the sand at the bottom of the hole was very soft and fine and dry, like sea-sand. And there were little shells in it. "Fancy it having been wet sea here once, all sloppy and shiny," said Jane, "with fishes and conger-eels and coral and mermaids." "And masts of ships and wrecked Spanish treasure. I wish we could find a gold doubloon, or something," Cyril said. "How did the sea get carried away?" Robert asked. "Not in a pail, silly," said his brother.