Hardly had Martine spoken when Priscilla, who was a few steps ahead of her, turned back with a cry of alarm.
"Look, Martine; what shall we do?"
Stepping up beside her friend, Martine too exclaimed in surprise.
"Do you suppose it will come any higher? I have heard of the rapid rise of the tide, but this has just rushed in."
Even in that first quick glance both girls realized that they were in a critical position. In going up to the "grotto," as Martine called it, they had taken no notice of tide-water marks, such as both of them might have observed. The rocky arms by which they had ascended were now covered by water, and an incoming wave dashed over Priscilla's feet as they stood there, uncertain what to do.
"Will it come all the way in? We shall be drenched if it does."
"No," said Martine, turning about and inspecting the nook where they had been standing when they heard Mr. Knight's voice.
"You can see that if the last high tide had come in lately as far as that little hollow, there would be some water there now. Instead, it is perfectly dry. You can prove that for yourself."
"Yes, yes, you are right; by standing back here we can at least keep dry, but oh, dear, when shall we get out?"
"Probably not until Mr. Knight rescues us," replied Martine, cheerfully, "and even he will hardly come to our relief until low tide, which is probably some hours away."