When I first glanced at the diagram in the lower left, my reaction was "No, no, that's spheroidal weathering." But while the two processes are different- erosional rounding is physical, and spheroidal weathering is predominantly chemical- the overall result is quite similar, just as the diagram shows. If you enlarge the photo to full size, you can read the text over to the right side, where it's cut off. With one minor exception, it's pretty good and accurate for a lay audience. And that minor exception really is pretty trivial: I don't think palagonite is really a mineral, it's more a mixture of microcrystalline minerals and amorphous materials. However, that's a picky technicality.