 Fossils known as <unk> and <unk> may represent members of microbial mat communities . <unk> appears on about a third of the slabs Caron and Jackson studied , and in some cases presents the wrinkled " elephant skin " texture typical of fossilized microbial mats . If such mats were present , they may have provided food for grazing animals and possibly helped to preserve soft bodies and organs , by creating oxygen @-@ free zones under the mats and thus inhibiting the bacteria that cause decomposition . 
