"But there are no grey hairs in rocks?" said Daisy.
"Yes, there are. Trilobites do just as well."
"But, I say," said Daisy, laughing, "how can you tell that the rock is old? You wouldn't know that grey hairs were a sign, if you saw them on young people."
"Pretty well, Daisy!" said the Captain, delighted to see her interested in something again; "pretty well! But you will have to study something better than me, to find out about all that. Only it is true."
"And you were not laughing?"
"Not a bit of it. That little fellow, I suppose, lived a thousand million years ago; may as well say a thousand as anything."
"I can't see how you can tell," said Daisy, looking puzzled.
"That was a strange old time, when he was swimming about or when most of them were. There were no trees, to speak of; and no grass or anything but sea-weed and mosses; and no living things but fishes and oysters and such creatures?"
"Where were the beasts then, and the birds?"
"They were not made yet. That's the reason, I suppose, there was no grass for them to eat."