Cross-Bedding, Bedforms, and Paleocurrents
   A companion to the book by David M. Rubin of U.S. Geological Survey. Images of real bedforms and cross-bedding as well as animated computer-generated images help to understand the building of sedimentary structures.
   http://walrus.wr.usgs.gov/seds/table_of_contents.html

Low-temperature formation of Dolomite and Magnesite
   Latest version (2005) of the open-access e-book authored by J.C. Deelmann on dolomitization and related phenomena. A total of 505 text pages, including a number of graphs, drawings and photographs.
   http://www.jcdeelman.demon.nl/dolomite/bookprospectus.html

Petrology of sedimentary rocks
   Although long out of print, the seminal book (a total of 182 pages in a single pdf file) by R.L. Folk (1974) remains an excellent resource if you are interested in sedimentary rocks.
   http://www.lib.utexas.edu/geo/folkready/