41. Tonight Mammoth Cave got a new voice. 42. The Mammoth Cave and its underground rivers. 43. You love Mammoth Cave -- you're changed ." 44. K�mper returned to Berlin, and from the point of view of the Mammoth Cave country, disappeared entirely. 45. Later he crossed the Allegheny Mountains, visiting the Mammoth Cave and other localities, and then traversed Canada. 46. Crystal Cave is now part of the Flint Ridge Cave System of the Mammoth Cave National Park. 47. At Harvard, McCombs studied with Nobel laureate Seamus Heaney, who encouraged him in his exploration of Mammoth Cave . 48. In 1941, Mammoth Cave National Park was established, and the two upper locks and dams closed in 1950. 49. Ecological restoration of this portion of Mammoth Cave , and facilitating the return of bats, is an ongoing effort. 50. Notable scientists who studied Mammoth Cave during this period include Patty Jo Watson ( see section on prehistory .)
