Step 1: What cleavage means.
Cleavage is the set of close parallel surfaces along which a deformed rock splits. How the splitting planes look depends on whether the minerals in the rock are spread out evenly or not.
Step 2: Even spread of minerals.
When the platy minerals are spread uniformly through the whole rock, the splitting surfaces are smooth and continuous everywhere. This gives continuous cleavage, of which slaty cleavage is the fine grained example.
Step 3: Uneven spread of minerals.
When the minerals are not evenly distributed and gather into thin zones or seams, the cleavage planes occur only along those zones and leave gaps in between. The cleavage is therefore broken up, or spaced.
Step 4: Why not transposition.
Transposition cleavage is about an older fabric being reoriented into a new one, not about uneven mineral spread, so it does not fit the clue.
Step 5: Match the clue.
The clue uneven distribution of minerals points straight to cleavage that is spaced rather than continuous.
Step 6: Answer.
Hence the cleavage formed in rocks with unevenly distributed minerals is spaced cleavage.
\[ \boxed{\text{Spaced cleavage}} \]