This argument increased my curiosity, and Addison now told me something about the so-called fortress. "It is a queer sort of place," said he; "a kind of knoll, with four or five prodigious great rocks around it. I guess we never have been over there since you came, though we passed in sight of it the day we went to dig out the foxes. It is on the line between Mr. Edwards' south field on one side, and the woods of our pasture where those big yellow birches and rock maples are, on the other. Those great rocks lie close together there, on that little knoll, just as if they had been dropped down there like so many big kernels of corn in a hill. "From what I have read about geology," continued Addison, reflectively, "I think it is likely that some mighty glacier, in long past ages, piled them there. One could imagine that a giant had placed them there, or had dropped them, accidentally out of his big leather apron, as he strode across the continent, in early times." "Oh, hear him!" cried Halse. "Ad will be out giving lectures on geology next!" "No," said Addison, laughing, "I don't want to give lectures. I don't know how the rocks got there, but they got there somehow, for there they are. Two of them, as Nell says, are almost as large as a house; and they all stand around, irregularly, enclosing a sort of little space inside them, as large as--how big is it, Doad?" "Oh, I should think that it was as large as our sitting-room," she replied. "It is bigger than that," said Ellen. "It is as big as the sitting-room and parlor together." "Perhaps it is," assented Theodora. "But it isn't like rooms at all; it is an odd place and there are nooks like little side rooms running back between where the sides of the great rocks approach each other. It is a real pleasant place, sort of gigantic and rustic. I don't wonder that Thomas and Kate like to go there." "None of these big rocks quite touch together," continued Addison, "but Tom has built up between them with stones, all around, except one narrow place which he calls the fort gate. He has built up all the open places, six or seven feet high, so that it is really like a fort: and he has made a stone fireplace against one of the rocks inside, with a little chimney of flat stones running up the side of the rock, so that he can have a fire there without being plagued by the smoke."