Yosemite Valley from Taft Point, California by ahochstaedter

The view from Taft Point shows many of the prominent features in Yosemite Valley. El Capitan, Cathedral Rocks, the Merced River, the Three Brothers, and Yosemite Falls are all visible. In addition to the classic U-shape of a glacially carved valley, the view shows the importance of rock granite composition and jointing in creating the morphology of the valley. Vertical jointing clearly visible in Cathedral Rocks on the left portion of the image opposite El Capitan tends to make spire- or pillar-like rock formations. Additional good examples of vertical jointing can be seen in the nearby rocks on the far right side of the image. In contrast, the jointing on the Three Brothers to the right of El Capitan is inclined at a 45 degree angle. The El Capitan Granite is relatively unjointed, which creates the clean granite face of El Capitan. The area to the left of El Capitan is known as The Rockslides. It is composed of a dark diorite that is much more heavily jointed than the El Capitan Granite, causing it to weather and erode into talus slopes rather than maintaining steep cliffs like the El Capitan Granite.

On the valley floor, the Merced River meanders back and forth across the valley. An oxbow lakes (or marshy areas) can even be seen in the meadow near the base of the Three Brothers. The Merced River meanders in this area because of its low graadient. The gradient is low becasue Yosemite Valley was dammed in Pleistocene times by the moraines of the Tioga glaciers. Although poorly revealed in this image, one of these moraines occurs near the base of El Capitan. In fact, it is called the El Capitan Moraine. This moraine dammed the Merced River about 20,000 years ago during the last ice age. The lake created by the moraine allowed sediment to accumulate in Yosemite Valley. In some places, as much as 2000 feet of sediment rests on top of bedrock. It is these flat lake sediments that cause the low gradient of the Merced River in this area. The El Capitan Moraine still acts as a sort of knickpoint for the Merced River. As can be seen in this image, rapids occur downstream from the El Capitan Moraine.