This story is part of story of the Treviño/Uribe Fort.

At the time that the walled fort was built(possibly 1853), a sundial was set above the portals of the entrance gate. The sundial has a story that goes with it.
To tell the story you have to go back a few years to Revilla. Cosme Damian Martinez and his cousin, Jose villareal, as 13 year olds, were captured by the indians and taken north into Texas. After about ten days of traveling, they managed to escape. First, they traveled north guided by the north star to throw off the indians then south, traveling at night and hiding during the day. After traveling for days they reached Palafox, a small town north of Laredo. There they were nursed back to health and taken back to Revilla.
Jose never forgot the importance of the stars for directions. When he was older on one of his trips to the  interior of Mexico, he saw a sundial set to point to the north star with an arrow in the center. He asked how it was done and learned all he could about making one. When don Blas Maria was building the fort, Jose asked don Blas Maria if he could make and set a sundial on the entrance. Jose was given permission to set the sundial. Jose made two stone blocks, polished on both sides with a small hole on the center for the iron arrow to be set. The hole was also used to set the stone on its final resting place on the mortar. The stone had to be set during the equinox.  The equinox is when the sun is directly over the equator, which is either March 21 or September 23. The stone had to be set at night with the hole for the arrow pointing to the north star. The arrow was then set on the hole to read time. The sundial shows time on the north side in the summer and the south side in the winter except for 2 or 3 days during the year.
      The original entrance to the fort was flat on top of the gate. The round part was added by don Blas Maria to accommodate the sundial.     

This was the monument that Jose Villareal made to the north star in appreciation for guiding him away from the indians and back to his home in Revilla.
The reason for Jose making 2 stones was in case one broke, he already had a second one ready. The second stone that was never used was wrapped in hides and buried in the fort grounds.
To this day, it has never been found.