As Millard’s course forward could end only in the sea, Jack now crouched low, stealing along a parallel course behind a low ridge of rock.

Then Millard suddenly stepped into a clump of tall bushes.  Though his game was now out of sight, Jack did not lose his nerve, for he could hear the fellow.

Spink! spank! clank!  The noise came from a shovel, vigorously used.

“Not a hard one to guess,” throbbed Captain Jack Benson, exultantly.  “He has brought his maps and his stolen records with him, and is burying them in this lonely spot until some other time when he’ll feel safe about coming back for them.  Talk about luck!  Why, Hal and I can pounce on this fellow, when he comes out over yonder, and, after we get him, we can next dig up whatever it is that this foreign agent thinks is worth burying!”

Then, with a shade of curiosity, Benson added to himself: 

“I don’t know, yet, how it happened that Hal was on my trail.  There wasn’t time for him to tell me.”

Clank! clank!  But after a while the noise of the shovel ceased for a while.  Captain Jack craned his neck eagerly, trying to pierce the darkness of the night.  He could make out nothing, though he heard some one still moving inside the clump of bushes.

Then again the noise of the shovel on the dirt was heard.

“He’s filling in, now, beyond a doubt,” thought Captain Jack.  “He is burying—­what?  The maps and records?  Hiding them here that he may dig them up at some later date?”

Benson chuckled noiselessly.

“If that’s Millard’s game I reckon some one else will do some digging over yonder before he pays this place a second visit!”

Ah, the noise had stopped, at last.  Now, Millard came out of the thicket.

“He hasn’t that bundle he brought up here!” throbbed Jack Benson.  “And he isn’t bringing a shovel out, either, so it must be hidden right handy.  Great!”

Mr. Millard could depart, now, if he wanted.  Jack trusted to his chum, prowling somewhere about, to have the good judgment to follow the long-legged fellow away.  As for Benson, he didn’t mean to do another thing until he had found the shovel, and had determined just what had been so carefully buried on this dark night!

So Jack watched, rather indifferently, as Millard slunk off into the darkness.  After three minutes or so had passed, Jack rose and ran straight for the thicket.

There it was—­new ground, that had just been turned over with a shovel.  There was no mound, but the fresh earth showed just where to dig.

“Oh, this is as easy as making change for a blind man!” chuckled the young submarine skipper, rubbing his hands ecstatically.

What about the shovel?  Jack turned to feel around in the darkness.  Really, Millard couldn’t be such a very clever fellow!  Jack had no difficulty in finding the shovel.  Its handle was sticking out from under a mass of dead brush.