Pipe Creek Sinkhole have also been found there. Pipe Creek Sinkhole preserves an ancient wetland. It was created by the collapse of a limestone cave in a Silurian reef formation. That left a steep-sided depression about long, wide and deep. When water collected in the depression, it became the habitat of the plants and animals whose remains were preserved there when the sinkhole was buried by glacial outwash and till during the Pleistocene Epoch, two million to 11,000 years ago. While the ecology of the Pliocene in North America is well-known from fossil discoveries in other places, notably coastal sites, the Pleistocene glaciers
A Void constraint to the original, avoiding the most commonly used letter of the alphabet. This precludes the use of words normally considered essential such as "je" ("I"), "et" ("and") and "le" (masculine "the") in French, as well as "me," "be," and "the" in English. The Spanish version contains no "a", which is the second most commonly used letter in the Spanish language (first being "e"), while the Russian version contains no о. The Japanese version does not use い ("i") at all. "A Void"'s plot follows a group of individuals looking for a missing companion, Anton Vowl. It is in part