Percy,
Google "spheroidal weathering images", now look at Edge's photo. The lower pinkish rocks are the granite, do you see the spheroidal weathering in the granite now? The granite was being weathered chemically but the weathered material was not being removed.
To weather a granite this deeply requires a substantial amount of time. It is an interesting photo because it is a picture of an unconformity that clearly shows a prolonged period of weathering before the later deposition. If everything weathered has been removed this is not as clearly shown.