Sedimentary rocks are laid down in layers called beds or strata. A bed is defined as a layer of rock that has a uniform lithology and texture. Beds form by the deposition of layers of sediment on top of each other. The sequence of beds that characterizes sedimentary rocks is called bedding.
Bedding types:
Parallel lamination where all sedimentary layering is parallel
Cross-bedding: Sometimes multiple sets of layers with different orientations exist in the same rock, a structure called cross-bedding. Cross-bedding forms when small-scale erosion occurs during deposition, cutting off part of the beds. Newer beds will then form at an angle with older ones.
Graded bedding is a structure in which beds with a smaller grain size occur on top of beds with larger grains. This structure forms when fast flowing water stops flowing. Larger, heavier clasts in suspension will settle first; smaller clasts follow later
http://en.wikipedia.org/wiki/Sedimentary_rock