Cool Rocks

I once found a river cobble that had so many chapters to its story. The reconstruction goes like this: Sedimentary (shale), + heat and pressure, metamorphosed into gneiss (precambrian). Fractured and intruded by hydrothermal fluids. Broken apart and tumbled into a river channel, buried and re-lithified into a conglomerate. Re-metamorphosed into a quartzite. Uplifted in a mountain chain, eroded out during Pleistocene, found by me on a terrace of river gravels like 10 yrs ago.