most of the animals even the fattest , slothful calves had taken to the hills as soon as the ominous black thing appeared , and though the nearest hill was an hour away on foot ( for the camels theyd tried to mount had shaken them off and fled as well ) , and theyd have to abandon the old and the infirm to their fate , perhaps there was still time to follow suit but right then the shaking ground beneath their feet began to burst open like a vast , festering wound , wide long chasms and gashes ripping in every direction and letting out thick white jets of steam , boiling water , and fiery chunks of molten rock .