It has been explained"-- she was looking at him now, quite interested in what she was saying--"by men who have visited these islands, that this is to be accounted for by the beds of gypsum that lie under the sand, for under some conditions the gypsum will dissolve." The explanation concerning the gypsum was certainly interesting, but the nature of the quicksand was not the point which Caius had brought forward.
"It is this fact, that one cannot tell where the sand will be soft, that makes it necessary to have a guide in travelling over the beach.

The people here become accustomed to the appearance of the soft places, but it seems that O'Shea must have been deceived by the moonlight." "I do not blame him for the accident," said Caius, "but for what happened afterwards." Her slight French accent gave to each of her words a quaint, distinct form of its own.

"O'Shea is--he is what you might call _funny_ in his way of looking at things." She paused a moment, as if entirely conscious of the inadequacy of the explanation.

"I do not think," she continued, as if in perplexity, "that I can explain this matter any more; but if you will talk to O'Shea----" "Madam," burst out Caius, "can it be that there is a large band of lawless men who have their haunts so near this island, and you do not know of it?
That," he added, with emphatic reproach, "is impossible." "I never heard of any such band of men." Madame Le Maitre spoke gently, and the dignity of her gentleness was such that Caius was ashamed of his vehemence and his reproach.

What he wondered at, what he chafed at, was, that she showed no wonder concerning an incident which her last statement made all the more remarkable.