OVERFLOW

"Deposits that show water arrived before fluvial sediments downstream
 of the bedrock high"

 Unlike the other three mechanisms, water associated with overflow transverse drainages reaches downstream of the bedrock high before any gravels associated with the upstream basin.  An overflowing lake spills water downstream across a bedrock high (upper image), but collects sediment from upstream of the bedrock high until the lake drains entirely.  For this reason, deposits associated with the rapid arrival of lake water, like lacustrine clays (middle image) or flood deposits, are deposited downstream before gravels and other sediments from upstream of the bedrock high (lower image).