 So the sedimentary rocks are very important. They cover almost the entire surface of the earth. There are places of weathering and erosion that are not covered with sedimentary rocks. But most of the surface of the earth that we interact with as humans has sedimentary processes happening and sedimentary rocks on the surface. And the bottoms of the oceans are covered in sedimentary rocks. Thus, they're very, very important to earth history and to the processes that are happening on the surface of earth and also some other planets. So for example, Mars also has an important sedimentary record. So the importance of sediments can be described as the volume or the amount that they cover the surface of the earth. There are also some very practical reasons. When you have erosion like in the mountains and deposition, you can tell by the characteristics of those rocks whether it was in rivers, lakes, oceans, affected by glacial processes, and things like that. So most of the sediments accumulate in lows. So for example, most of our record of earth history is in rocks that were deposited in the oceans or marine environments. And we can look at those rocks to reconstruct the characteristics of earth history. That's one of the really important uses of sedimentology and stratigraphy. For example, we can understand changes in environment through time. We can understand the evolution of animals and the fossils that are preserved in those records through time. Another important key aspect of sedimentary rocks is resources. So one of the most valuable natural resources in California is actually sand and gravel for construction. And a lot of that comes from sediments that were deposited by rivers and transported by rivers. Our aquifers are also almost exclusively hosted in sedimentary rocks. So in Davis, the water can taste pretty bad. And that's in part reaction of the groundwater with the host rock sediments. And when you're drinking straight river water, which is a larger proportion of Davis water recently, the characteristics of that water are actually different. Sedimentary rocks also are the main source of petroleum products. The organic matter that's buried with the sediments in the oceans or sometimes in Martians decays as it gets buried and it converts into oil and natural gas. And then it's often hosted in sedimentary rocks. It sort of migrates up in pools where it can be collected as a resource. And then there are also important minerals in sedimentary rocks. So for example, in the Sierra Nevadas, there were gold veins that he wrote it out. And the gold was transported in rivers and concentrated based on the fluid dynamics into certain places where a lot of gold was found. So some of the gold was mined directly from veins, but a lot of it came from these fluvial deposits. The process of mining that gold involved hydraulic mining, which was mobilizing the sediment and using sediment transport processes and characteristics that we'll talk about later to concentrate the gold, that put a lot of sediment into the California rivers, which changed the flood behavior and the characteristics of the sediment. So we still see the effects of that sediment influx today. So overall, sedimentary rocks are really important. They cover a large part of Earth's surface. They record very important events, and they host a lot of resources that are important to people. Thanks for watching.