Editing Inner Space Cavern (section)

== Geology ==
{{For|details on the region's [[geology]]|Edwards Plateau}}

=== Speleogenesis ===
Inner Space Cavern lies within limestone and dolomite rocks of the [[Edwards Group]] formed during the [[Cretaceous period]].<ref>{{Cite journal|last1=Jasek|first1=James|last2=Russell|first2=William|last3=Lundelius|first3=Dr. Earnest|date=September 1975|title=the Texas Caver|url=https://digital.lib.usf.edu//content/SF/S0/05/50/46/00001/K26-04597-1975-v20-n09.pdf|journal=Texas Caver|volume=20|pages=131–148}}</ref> Following the formation of the [[Balcones Fault]], a series of vertical fractures through the Edwards Formations allowed ground water to freely move through the limestone marking the beginning of the cavern's formation. As water from the surface became ground water, [[carbon dioxide]] (CO<sub>2</sub>) was picked up from the atmosphere and from decaying organic matter, creating [[carbonic acid]] (H<sub>2</sub>CO<sub>3</sub>), which would react with and dissolve the limestone rocks creating voids. Over millions of years these voids grew leaving behind large rooms and passages. 

=== Fossil Record ===
There were several large openings to the caverns during the [[Ice age|Ice Age]], an evidence of several skeletons of prehistoric Ice-Age animals including a baby [[mammoth]], [[Ground sloth|giant sloth]] and the [[Smilodon|saber-toothed tiger]]<ref>{{cite web|url=https://books.google.com/books?id=Gy4EAAAAMBAJ&q=innerspace+and+saber+tooth+tigers&pg=PA12 |date=March 1979 |title=Underground Gourmet - Inner Space Caverns |work=[[Texas Monthly]] |access-date=September 22, 2019}}</ref><ref name=KDH>{{cite web|url=http://kdhnews.com/news/ancient-cave-underneath-highway-in-georgetown-worth-exploring/article_1a1d4824-e9b5-11e3-98c9-001a4bcf6878.html |title=Ancient cave underneath highway in Georgetown worth exploring |last=Rafique |first=Sarah |work=[[Killeen Daily Herald]] |date=June 2, 2014 |url-access=subscription |access-date=September 21, 2019}}</ref> have been found in the cavern; many were trapped in the cavern after they fell through the opening, unable to escape, and others drowned in thick, [[quicksand]]-like mud at the bottom of watering holes. Some filled-in [[sinkhole]]s have been found, including the prehistoric entrance to the cavern. All natural entrances closed approximately 14,000 years ago.