Changes

Sedimentary rocks are formed by sand and other sediments which settle out of suspension in water, as well as minerals which dissolve in water (which sand cannot do)<ref>http://pearsonkt.com/summaryStreetOT/texts/Sci-National-Grade-4/iText/products/0-328-34278-5/unitc/ch11/331.html</ref> and the hard parts of small aquatic organisms such as [[plankton]], which accumulate on the bottom of a body of water and undergo [[lithification]]. Although only about 8% of the earth's rocks are sedimentary, 75%-80% of the Earth's land area is covered in sedimentary rock.[http://honolulu.hawaii.edu/distance/gg101/Programs/program21%20SedimentaryRocks/program21.html] Therefore, geologists point out, there is irrefutable evidence that at least 75% of the Earth's land was once covered in water.