I've been working on some ideas about these rocks, I posted some ideas deep in a previous thread.

I'll have to search for the front haz cam to see which rock we are looking at here. Is it similar to the "conglomerate?" (that's the last time I use conglomerate, 'cause I don't see them here, and the implication is of high-energy deposition. But I'll remind some readers that lag deposits in aeolean systems can create conglomerates and there are volcanic breccias as well.)

What I think we are seeing:

Columbia Hills are a sequence of basalt flows. Between eruptive events, small scale hydrothermal systems or weak fumeroles locally alter the tops of the most recent flow.

And / Or, we are seeing small scale examples of Nick's Sabkha model. Local groundwater near surface and occassionally at surface alters the top of a basalt flow. Along comes another basalt flow which shuts the system down, only to have it occur at the next flow top. Hot basalt flows also interact with surficial deposits at their base.

And Wishstone type rocks are late-stage sills or dikes intruded into the basaltic pile.

jms