Though it was only preparation for the main job, great obstacles had already been overcome. Very little masonry had ever been done in the presidio, and, with the exception of the imported artisans, the workmen had to be trained. Even the imported ones had much to learn about coquina, the natural shellrock peculiar to this section of Florida. Coquina is nothing more than broken sea shells cemented together by their own lime. Where the layer of shells has been under great pressure, the rock is solid and hard; where pressure has been less, the stone is coarse and easily crumbled. The men had to become expert in grading the stone, for only the hardest and finest rock could go into the fortification. There was also a shortage of common labor. When there should have been 150 men to keep the 15 artisans working at top speed—50 in the quarries and hauling stone, 50 for gathering oyster shells and helping at the kilns, and another 50 for digging the foundation trenches, carrying the baskets of sand, and mixing mortar—it was hard to get as many as 100 laborers on the job. Indians from three Nations, the Guale (Georgia), Timucua (eastern Florida) and Apalache (western Florida), were called upon for labor. Some of them had to travel 80 leagues to reach the presidio. Many of them served unwillingly. There were serious domestic problems, for these peons had the choice of bringing their families with them or leaving the women and children in the home villages to eke out their own living. In some cases, not even the chiefs were exempt from the draft. In theory each complement of Indian labor served only a certain length of time; in practice it was not uncommon for the men to be held much beyond their assigned time, either through necessity or carelessness. One wretched chief was forced to labor on the works for more than 3 years without once returning to his own lands. Some of the Indians were used as servants by the Governors. True, the Indians were paid for their labor. Even the Apalaches, condemned years before to labor on the fortifications as the penalty for rebellion, apparently received a wage. The Indian peon was cheap labor—1 real (12½¢) per day, plus rations of maize—but he was not good labor, for by nature the Indian was unfit for heavy work on a European-style fortification. A brave might play the bone-breaking game of Indian ball for a full day, but he could not stand up under the “day-in, day-out,” grinding, back-straining labor of the quarries. Not all the Indians, however, were common laborers. A half dozen developed into carpenters, and though they did not receive the top wage of 10 to 12 reales, they seemed well pleased with their 8 reales—which was twice what apprentice carpenters earned.