“Can you read any thing further?” “Yes: One day, long ago,--was it at the close of the Carboniferous or the beginning of the Permian age?--there was a rain-storm here. It came up with a strong wind, from the south; the drops fell heavily, and were very large. I think it must have been what we call a ‘black squall.’ It soon passed, and the sun shone out hot.” “Oh, oh! now you are guessing at what might have been!” “Not at all. I am reading what really was. Are not these rocks my books? Look now at this ledge. Here is a thin layer of mud-rock, as well as of sandstone. Here was some marl-mud laid down. I think that here must have been an inlet. Observe here on this exposed surface, these pits or dents. You can put your finger tip in them. See how they slant from the south, and how deeply they are driven into the sand. Suppose now that we stood by a low level beach of sand and marl-mud, and a sharp shower, driven by a strong wind, came up from the south, and the big rain-drops pelted violently on the sand and mud. Would they not leave marks identical with these? So we know that here were big rain-drops from a southerly gust. We know that it was soon over; for if rain had fallen long, all the surface of the sand would have been washed and saturated, and prints of individual drops would have been obliterated. We know that the shower was followed by a hot sun, and as the sun was very hot, we infer that the time was somewhere in the middle of the day, between ten and four, the time when the sun rays are most powerful. We know that the sun was hot, because these rain-marks dried quickly, before they had time to lose the sharpness of their imprint. It is also evident that such delicate markings must have been quickly covered up, else the next heavy mist or drizzle of rain, or creeping tide, would have smoothed them out. Therefore, I make a guess that when the marks had dried hard, being sun-baked as some bricks are, a strong breeze came up, sweeping sand before it, and so buried the prints under sufficient sand to protect them; or, possibly, a fresh layer of ooze, or mud and sand mixed, came down the estuary and rolled gently over these rain-prints and cased them safely.” “Who would have thought of reading all that in sand!”