The Coming Wave by Oliver Optic

Leopold was terribly startled when he heard the voice of Stumpy. He was the possessor of a mighty secret, and he felt that he had been very imprudent in exposing it to discovery. It would have been better to dig up the hidden treasure in the daytime, when the light would have enabled him to observe the approach of an intruder. But he was glad it was Stumpy, rather than any other person, who had detected him in his strange and unseasonable labor. If need be, he could reveal the great secret to his friend, which he would have been very unwilling to do to any one else. But he did not wish to say a word about the hidden treasure even to Stumpy.

He was startled when he heard the voice of his friend, and, without deciding at that moment upon his future course, he dropped the shot-bag into the hole from which he had taken it, and hastily covered it with sand to the depth of a foot, in fact, filling up the smaller hole he had made. This was the work of a moment; and before Stumpy had time to approach the spot, Leopold, with the lantern in his hand, walked to the place where his friend had landed.