Their standard unit of measurement is the vara (33 1/3”). They also use a League, a Labor, a Sitio in their descriptions. What is most interesting is that land was formed under Spanish Law(1720-1821), then Mexican law(1821-1836), then Texas as a Sovereign Nation(1836-1845), then as part of the US. With each change they respected the previous laws so when you look at a deed, you have to see what year it was granted.

-Derek Zeman