We had been inspecting the inner courtyard; Edith and Thora were getting together our lunch.
I came out of the vault of Chau-te-leur to find Stanton before a part of the terrace studying it wonderingly.
"'What do you make of this ?' he asked me as I came up.

He pointed to the wall.

I followed his finger and saw a slab of stone about fifteen feet high and ten wide.

At first all I noticed was the exquisite nicety with which its edges joined the blocks about it.

Then I realized that its colour was subtly different--tinged with grey and of a smooth, peculiar--deadness.
"'Looks more like calcite than basalt,' I said.