She thought. “No, it hasn’t.” She’d have heard. “So what’s caused it?”

“Well, hell, I don’t know. I’m no scientist. I’m just an observant copper, like you. What else do you notice?”

She looked around, trying to take in the scene as a whole. Her skirt flapped around her legs, irritating her.

“I think the profile has changed. Of the Seat.”

“Very good. On the slope we’re standing on, which is no more than six or eight per cent, I’d say there has been a slip, overall, of ten or fifteen feet. And in the steeper slope at the back of the Dry Dam, for instance, it’s a lot more than that.”

“You think so?”

“You can hear it. Especially at night. Rock cracking. Little earthquakes, that shake the foundations of your house.”

She stepped forward, cautiously; she had no desire to imitate the fate of Ted’s pebble. When she’d got to where she judged the edge of the dust pool to be — still standing on firm, unbroken basalt, maybe three feet from the lip of the dust — she crouched down.

The dust was fine-grained, like hourglass sand. It seemed to be shifting, subtly, in patterns she couldn’t follow. It was more like watching boiling fluid than a solid.

She thought she could smell something. Perhaps it was sulphur, or chlorine.

Occasionally she thought she could see some kind of glow, coming from the dust where it was exposed. But it was sporadic and half-hidden. She’d once flown over a storm in a 747; looking out of the window, at lightning sparking purple beneath cotton-wool cloud layers, was something like this.

“Come on,” Ted said. “I need to show you something else.” He headed down the slope, and started walking around the pool.

She straightened up carefully, and went to follow Ted.

She said, “You think this has something to do with the loss of the lines? The TV and gas and phone—”

“I wouldn’t be surprised,” he said mildly. “Can’t say how far underground it spreads, how far it has got.”

“But if there are land slips going on, some kind of subsidence—”

“You could get line breaks. Yes. There have been scientists up here, poking and prodding away. There’s an American chap my son works with… But they’re just recording, measuring. I think someone should be doing something. Taking it a bit more seriously.”

They climbed around the crag. They were paralleling the edge of the funny dust, Morag saw. It made for a rough circle, she supposed, patches of it draped across the breast of the land. But the edge of the circle was rough and irregular; in some places necks of the dust and broken ground came snaking down the hillside, perhaps carried there by some slip or a fault in the basalt, and they had to descend to avoid it.