Sinkhole may exhibit a visible opening into a cave below. In the case of exceptionally large sinkholes, such as the Minyé sinkhole in Papua New Guinea or Cedar Sink at Mammoth Cave National Park in Kentucky, an underground stream or river may be visible across its bottom flowing from one side to the other. Sinkholes are common where the rock below the land surface is limestone or other carbonate rock, salt beds, or in other soluble rocks, such as gypsum, that can be dissolved naturally by circulating ground water. Sinkholes also occur in sandstone and quartzite terrains. As the rock dissolves,
Bayou Corne sinkhole of the damage it has caused, which sent former and current residents of the town into a frenzy as a heated debate ensued over whether the company believed to be responsible for severe damage and loss of homes should be given permission to tamper more with an area already considered to be "deeply contaminated," as environmental activist Nara Crowley stated. In July 2015, Texas Brine began a series of lawsuits against Occidental Petroleum, claiming that an oil well drilled by Occidental Petroleum in 1986 triggered the cavern wall break that led to the creation of the sinkhole. Texas Brine is