ten o'clock
But greater even than the need of arms was that of ammunition . If Urrea were able to seize the schooner , or to take the supplies , the moment after they landed , he would strike the Texans a heavy blow . Hence the six now pushed their horses . At ten o'clock , they caught a glimpse of the sea upon their right . Five minutes later they saw a cloud of dust on their left , less than a mile away . It was moving rapidly , and it was evident at once that it was made by a large body of horse . When the dust lifted a little , they saw that it was Urrea and his men .