"What's that?" Hopalong suddenly demanded, drawing rein and listening. A dull roar came from the dam and he instinctively felt that something was radically wrong.

"Water, of course," Red replied, impatiently. "This is a storm," he explained.

Hopalong rode out along the dam, followed by Red, peering ahead. Suddenly he stopped and swore.

"She's busted! Look there!"

A turbulent flood poured through a cut ten feet wide and roared down the other side of the embankment, roiled and yellow.

"Good G-d! She's a goner shore!" cried Red excitedly.

"It shore is—No, Red! It's over th' stone work—see where that ripple runs? We can save it if we hustle," Hopalong replied, wheeling. "Come on! Dead cows'll choke it—get a move on!"

When Buck had decided to build the dam he had sent for an engineer to come out and look the valley over and to lay out the lines to be followed. The west end, which would be built against the bluff, would be strong; but Buck was advised to build a core of rubble masonry for a hundred feet east of the centre, where the embankment must run almost straight to avoid a quicksand bottom. This had been done at a great increase over the original estimate of the cost of the dam, but now it more than paid for itself, for Antonio had dug his trench over the rubble core—had he gone down a foot deeper he would have struck it and discovered his mistake.

Hopalong and Red raced along the dam and separated when they struck the plain, soon returning with a cow apiece dragging from their lariats, which they released and pushed into the torrent. The bodies floated with the stream and both men feared their efforts were in vain. Then Hopalong uttered a shout of joy, for the carcasses, stranding against the top of the masonry core, stopped, the water surging over them. Racing away again they dragged up more cows until the bodies choked the gap, when they brought up armfuls of brush and threw them before the bodies. Then Red espied a shovel, swore furiously at what it told him, and fell to throwing dirt into the breach before the brush. He had to take it from different places so as not to weaken the dam, and an hour elapsed before they stopped work and regarded the results of their efforts with satisfaction.

"Well, she's there yet, and she'll stay, all right. Good thing we didn't take th' hill trail," Hopalong remarked.

"Somebody cut it, all right," Red avowed, looking at the shovel in his hands. "H2! Hoppy, see here! This is their work!"

"Shore enough H2 on th' handle, but Meeker an' his crowd never did that," Hopalong replied. "I ain't got no love for any of 'em, but they're too square for this sort of a thing. Besides, they want to use this water too much to cheat themselves out of every chance to get it."

"You may be right—but it's d—d funny that we find their shovel on th' job," Red rejoined, scowling at the brand burned into the wooden handle.