The Matlin quadrangle, located in Box Elder County, northwestern Utah, was selected for detailed geologic study because of the extensive Quaternary deposits of Lake Bonneville present in a region with no major sediment sources or tectonic activity. The mapping showed a well-preserved record of deposits laid down as the lake filled and emptied. The Transgressive Systems Tract is composed of a series of backstepping barriers formed as the lake rose to the Bonneville shoreline. The Highstand Systems Tract consists of the Bonneville shoreline. The subsequent catastrophic drop in lake level associated with the Bonneville flood stabilized at the level of the Provo shoreline, which is interpreted as a Falling Stage Systems Tract deposit. The Bonneville sequence then records a drop in lake level that marks the end of the sequence. The data collected during this study and from literature sources suggest that Lake Bonneville should be considered a Balanced-Fill lake.