"I'll let him give us a lead," said Sandy, "soon as we hit the lava. We can foller his trail that fur. Sit tight, son." Grit whined but subsided under the restraining hands.
"How about a drink 'fore we tackle that?" asked Sam, nodding at the shimmering view.
"Better hold off for a while." Sandy took the lead, bending from the saddle, reading the trail that Grit's paws had left in the alkali and sand. Cactus reared its spiny stems or sprawled over the ground more like strange water-growths that had survived the emptying of an inland sea than vegetation of the land. Once the dog's tracks led aside to a scummy puddle, saucered by alkali, dotted with the spoor of desert animals that drank the bitter water in extremity. Then it ran straight to a wide reef of lava. Sandy set down the collie. Grit ran fast across the pitted surface, ahead of the horses, waiting for them to cross the lava. They had hard work to get him to come to hand again, but he gave in at last to the knowledge that they would not go on otherwise.
"Sand's too hot fo' yore pads, dawg," said Sandy, "Raise the mischief with that tape. Shack erlong, Pronto. Give you a slice of Pedro's dried-apple pie when we git back, to make up for workin' you Sunday." The pinto tossed a pink muzzle and his master reached to pat the dusty, sweat-streaked neck. Alkali rose about them in clouds. Grit's trail, though blurred in the soft soil, was plain enough. The two riders went silently on at a steady walking gait. Talk in the saddle with men who make range-riding a business comes only in spurts.
"Never see a prospector with a dawg afore," said Sam at last. "An' that a sheep dawg."
"Dawg 'ud be apt to tucker out in desert travel," agreed Sandy. "Mean one more mouth fo' water."
He, like Sam, speculated on the kind of man P. Casey—if it was Casey they were after—might be. If not a sheepman or a prospector, a third probability made him an outlaw, a man with a price on his head, hiding in the wilds from punishment. It sufficed to them that he was a man whom a dog loved enough to bear a call to help his master.
Slowly, the mesa ahead took on more definite shape. The shadows resolved themselves into ravines and cañons. They entered a gorge filled with boulders and rounded rocks, over which the sure-footed ponies made clattering, slippery progress. Here and there the gaunt skeleton of a tree, white as if lime-washed, showed that once cottonwoods had flourished before the devouring desert had claimed the territory. The cactus was all prickly pear, the gray-green flesh of the flat leaves starred with brilliant blossom. Along one side of the cañon, mounting zigzag, showed the remains of a road, broken down by landslip and the furious rush of cloud-burst waters.
Making this, finding it free of wagon sign or horse tracks, Sandy picked up Grit's trail once again. The collie wriggled, shot up its muzzle, whined, licked Sandy's face.
"Nigh there," suggested Sam. Sandy nodded and let the dog get down. Grit raced off, nose high, streaking around a curve. When they reached it he was out of sight. The road had been built up in places on the outer edge with stones, dry-piled. They had fallen away, the grade following, so that sometimes all that was left for passage was a ledge along which the horses sidled carefully in single file, stirrups brushing the inside bank. The zigzags ended, the cañon narrowed, deepened. Sandy looked down to the dry bed of it four hundred feet below. The road rose at a steep pitch, cliff to the right, precipice to the left, stretching on and up to the summit of the pass.