<P> A karst fenster occurs when an underground stream emerges onto the surface between layers of rock, cascades some distance, and then disappears back down, often into a sinkhole . Rivers in karst areas may disappear underground a number of times and spring up again in different places, usually under a different name (like Ljubljanica, the river of seven names). An example of this is the Popo Agie River in Fremont County, Wyoming . At a site simply named "The Sinks" in Sinks Canyon State Park, the river flows into a cave in a formation known as the Madison Limestone and then rises again 800 m (⁄ mi) down the canyon in a placid pool . A turlough is a unique type of seasonal lake found in Irish karst areas which are formed through the annual welling - up of water from the underground water system . </P> <P> Water supplies from wells in karst topography may be unsafe, as the water may have run unimpeded from a sinkhole in a cattle pasture, through a cave and to the well, bypassing the normal filtering that occurs in a porous aquifer . Karst formations are cavernous and therefore have high rates of permeability, resulting in reduced opportunity for contaminants to be filtered . Groundwater in karst areas is just as easily polluted as surface streams . Sinkholes have often been used as farmstead or community trash dumps . Overloaded or malfunctioning septic tanks in karst landscapes may dump raw sewage directly into underground channels . </P> <P> The karst topography also poses difficulties for human inhabitants . Sinkholes can develop gradually as surface openings enlarge, but progressive erosion is frequently unseen until the roof of an underground cavern suddenly collapses . Such events have swallowed homes, cattle, cars, and farm machinery . In the United States, sudden collapse of such a cavern - sinkhole swallowed part of the collection of the National Corvette Museum in Bowling Green, Kentucky in 2014 . </P> <P> Interstratal karst is a karstic landscape which is developed beneath a cover of insoluble rocks . Typically this will involve a cover of sandstone overlying limestone strata undergoing solution . In the United Kingdom extensive doline fields developed at Mynydd Llangynidr across a plateau of Twrch Sandstone overlying concealed Carboniferous Limestone . </P>

What is karst topography what type of rock and atmosphere is responsible for their formation