Whenever you see brackets that means that the editor has added an explanation.  In this case [organic remains] was added to explain the word 'they'.  While W&M; used the word fossil in the previous sentence it is clear that they were referring to organic remains because by definition, recently buried remains (such as what is "now occurring") are not fossils.  From the "Dictionary of Geologic Terms", 3rd edition, 1984, by Bates and Johnson:  FOSSIL:  Any remains, trace, or imprint of a plant or animal that has been preserved in the earth's crust since some past geologic or prehistoric time.  Nothing buried in the present can be a fossil, for it is in historic time.  And further, you do not quickly bury fossils to preserve them, you quickly bury organic remains to protected them long enough so they they can eventually become fossils in some future geologic era.

W&M; likely used the term fossil loosely, like many editors of this WP page, to refer to organic remains that might become fossils per definition in some geologic era in the future.  It is unfortunate that W&M; were not as precise as they might have been, because uninformed people, such as Talk.Origins, misunderstand and twist what they said.

As much impact as W&M; have had on Creationary thought, nearly all fellow creationist today recognize that The Genesis Flood, is now way out of date.  Modern creationary geologists have moved well beyond The Genesis Flood.  When critics quote it, it displays their complete lack of competency on modern creationism.