As shown in the cross-section, the Merriam thickens from <1m at channel margins to 4 m in the channel low, about a five-fold increase.

Note thickening into channel low of a fossiliferous shale unit near the top of the Merriam, and the Hickory Creek Shale , whereas the uppermost Merriam strata maintain consistent thickness and facies.

As shown in the photo on the left, Merriam beds are truncated moving from channel low (left) toward the margins (right). These beds of skeletal WS-PS contain similar fauna as the coated-grain GS developed on surrounding highs, and are considered to be time-equivalent deposits.