The Mad Moravian had plenty of time in jail to contemplate the errors of his ways. He also had plenty of time for other things, like looking for a way to escape. In the process of trying various methods to get out of prison earlier than the law would have liked to allow, MM did some chiseling. After removing some of the cement between the cinder blocks, he was able to move a few of the blocks. In the middle of one of the blocks he found an interesting document.
Apparently, Antonin Dvorak had been held prisoner in the exact same cell, many years earlier. During his incarceration he had access to pen and paper and whiled away his days composing more music. It is uncertain whether he took any music with him when he got out of prison, but he did leave at least one piece behind.
Looking it over closely, it appeared to be a sketch for a melody for another Slavonic Dance, one of Dvorak's more famous works. But, to the Mad Moravian's eye, it was much more. He had many months to contemplate this work while in a Prague prison. Looking at it over that time he was able to translate it into a location on a map. He was pretty certain that Dvorak had never travelled to Houston but just in case he had, the Mad Moravian travelled to the spot the music indicated.
Upon arrival, he was unable to find anything that Dvorak might have left but the land might have swallowed it up over the years, or floods might have washed it away. He'd come prepared for just such a situation. He had a specially painted box and some special treasures to place at that location. He'd found a copy of a CD of Dvorak's Slavonic Dances. He'd also found one of his treasures that did not get transformed into worthless knickknacks: an 1897 Morgan City Silver Dollar.
There are additional hints for this cache in two other local caches: GCMZ00 and GCRVGR. A different hint in each cache.