 this picture you've got all these cracks developed over here. Imagine a second flood coming through here, a relatively gentle flood, you know water slowly flowing in here, a new layer of silt and sand and shales and clays. What's going to happen? It's going to, all of that new material is going to filter down into these cracks and it's going to solidify in there as the water evaporates out of it, all right? So now a hundred million years goes by and we come along and we cut this open and we look at this layer and we look at these and we'll see mud cracks and we'll be able to tell that that layer of rock was oriented this way because these mud cracks all start wide at the top and get narrow going downwards, all right? And it quite often happens that these strata of rock because the incredible forces of nature of plates coming together will take these layers and just flop them over upside down and we come along and we look at them and you can't tell which way's up, which way's down until you find one of these mud cracks and then even if the layer's upside down then you'll have these mud cracks teeping upwards and you'll say, whoa, this thing must have been flopped over and turned over upside down and it's the same processes I'm doing a Richard here. It's the same processes that produce these mud cracks, we'll fill them in and then maybe after a hundred million years they'll get fossilized, turned into a hard clay layer and then turned upside down but we'll still be able to tell what we call the stratigraphic relationship, the time relationship, which is older, which is younger because clearly this is older than whatever would lay on top of it.