“I see none here,” said Dan, leaning on his shovel and looking about him.  “The tide hath swept everything as clean as a floor.”

“I ’ll seek for some while thou art busy with the digging,” said Nancy, glad to escape the duty of picking up the clams, and off she trotted without another word.  The flats, seamed and grooved with channels where pools of water still lingered, sloped gently down to the lower level of the bay, and farther out a range of rocks lifted themselves above the sandy waste.

[Illustration]

“I ’ll surely find seaweed on the rocks,” thought Nancy to herself as she sped along, and in a few moments she had reached them, had tossed up the basket, and was climbing their rugged sides.

“There ‘s a mort o’ seaweed here,” she said, nodding her head wisely as she picked up a long string of kelp; “I can fill my basket in no time at all.”  There was no need for haste, she thought, so she sat down beside a pool of water left in a hollow of the rocks, to explore its contents.  The first thing she found was a group of tiny barnacles, and for a while she amused herself by washing salt water over them to see them open their tiny cups of shell.  In the pool itself a beautiful lavender-colored jelly-fish was floating about, and just beyond lay a star-fish clinging to a bunch of seaweed.  She found other treasures scattered about by the largess of the tide—­tiny spiral shells, stones of all colors, and a horseshoe crab, besides seaweed with pretty little pods which popped delightfully when she squeezed them with her fingers.  Then she heard the cries of gulls overhead and watched them as they wheeled and circled between her and the sky.  When they flew out to sea she sat with her hands clasping her knees and gazed across the bay at the three hills of Boston town.  She could see quite plainly the tall beacon standing like a ship’s mast on top of Beacon Hill, and farther north she strained her eyes to pick out Governor Winthrop’s dwelling from the cluster of houses which straggled up the slope of Copp’s Hill and which made all there was of the city of Boston in that early day.

[Illustration]

For some time she sat there hugging her knees and thinking long, long thoughts, and it was not until the sound of little waves lapping against the rocks roused her that she woke from her day dream and realized with terror that the tide had turned.  The channels and lower levels of the bay were already brimming over, and the water was deep about the rocks on which she perched.  At almost the same moment Dan had been surprised by a cold wave which washed over his bare feet, and, turning about, was dismayed to find a sheet of blue water covering the bay and to see Nancy standing on the topmost rock shouting “Dan!  Dan!” at the top of her lungs.  For one astonished instant he looked at her, then, throwing down his shovel, he plunged unhesitatingly into the icy bath.  And now Nancy, realizing that there was not a moment to lose if she hoped to reach the shore in safety, let herself slowly down off the rocks, leaving the basket behind her, and started toward her brother.