Meanwhile, at the Northern end, I notice what appears to be a conglomerate rock of some kind. "Conglomerate is a clastic sedimentary rock made up of rounded clasts that are greater than two millimeters in diameter. The spaces between the clasts are generally filled with sand and clay-size particles. The rock is bound together by a cement that is usually composed of calcite or quartz."
Of interest: "Clastic rocks are composed of broken pieces of older rocks (clasts)."