In those two cross-sections, why is the conglomerate in a bowl-shaped deposit

http://spot.pcc.edu/~epuris/Busch_Fig8.11&12&9.pdf

The conglomerate deposits are labelled S, H, and Z in the cross-sections.

The traditional U shaped erosion pattern is created by a glacier, however, there is no indication of scale on the cross section and I'm assuming the building, trees and truck are not to scale. A river can cut U shaped section through the underlying bedrock which in Fig: 8.11 is an unconformable siltstone bed overlaying a gravel bed (I don't like the term gravel)
My guess would be that it is a channel cut out by glacial movement and the conglomerate is melt out till.