All the while the lead mule, held to one place by a grip that never relaxed for an instant, plunged and reared and strained every nerve to unseat his rider. Next came a salvo of shouts and objurgations, and two of the packers hurtled along the trail, sawing at the mouths of their animals, but utterly unable to hold them in, and indeed, narrowly escaping being ridden over by the rest of the pack mules following. Saracen always declared that his mule counted each animal as it went by, but certain it is that no sooner had the last of the pack train vanished in the distance than the lead mule steadied down. No damage had been done save that the rider's hat, though strongly fastened on, had been bucked off. A few minutes later, back came the other men, who curiously enough were in similar case. The three hats were found close together on the trail. When an investigation was made, no known cause could be found to account for the sudden bolt, except that a white mule, one of the last in the train, had become suddenly frightened, possibly because there was a bear in the neighborhood, and had started to run, bunting into the mule next in the lead, and thus communicating the fright all the way along the line. Fortunately no mishaps had occurred, and though some of the packs had shaken loose, none had been thrown and nothing was lost. The very next day after this, the mule in question, which, by the way, was the only white mule in the party, quietly slipped off the side of a cliff with a drop of one hundred and forty feet, landed upside down on the pack-saddle, bounced twenty feet farther, and then quietly got up, shook himself, and began to graze. Being white, the mule was easily visible, and as it was seen that he was not hurt and in the pack were certain things almost indispensable, it was decided to go down and recover him. When this was pointed out, Roger, thinking that it might take some time to recover the mule, felt that he would be wiser to start on his journey for the Canyon, and finding out the nearest trail from the chief of the party, he started back to fulfil his "engagement with the sun." Having plenty of time, he took the trip quietly, reaching Lone Pine a few days later, and making his way south to the railroad at Mohave. [Illustration: IF HE SHOULD SLIP! The Chief Geographer making a plane-table station, 10,996 feet above sea level. Note how table is tied on. _Photograph by U.S.G.S._] There he encountered a young fellow on his way to Washington with some special news of the discovery of important fossils by one of the branches of the Geological Survey, and Roger, to his surprise, found another avenue of science covered by that department of the government to which he had become so proud of belonging. This young fellow had been working in the bone-bearing strata for several months, and some extremely valuable finds had been made which were to be placed in the Smithsonian Museum.