By Size:
* Boulders: Large, rounded rocks that were transported by the stream during high flows.
* Cobbles: Smaller, rounded rocks that are still easily visible and can be picked up by hand.
* Pebbles: Small, smooth rocks that are usually less than 2.5 inches in diameter.
* Sand: Tiny rock fragments that are visible to the naked eye.
* Silt: Very fine sediment particles that are too small to see individually but give the stream a muddy appearance.
* Clay: The finest sediment particles, so small that they can only be seen with a microscope.
By Origin:
* Bedrock: Pieces of the underlying rock that have been broken down by erosion.
* Soil: Fine particles of decomposed organic matter and minerals transported from the surrounding land.
* Organic Debris: Leaves, branches, and other plant matter that falls into the stream.
* Animal Remains: Shells, bones, and other animal parts that have been transported by the stream.
* Artificial Materials: Plastics, glass, and other human-made materials that have been discarded in or near the stream.
Example Scenarios:
* Upstream: A stream flowing through a rocky mountain area would likely have a mix of boulders, cobbles, and pebbles, with some sand and silt.
* Downstream: A stream flowing through a flatter area with more vegetation would have a mix of fine sand, silt, and clay, along with organic debris.
Important Note: The specific type and amount of sediment found in a stream can vary greatly depending on factors like the stream's gradient, flow rate, and the type of surrounding land.
