Occurrence of Attributes in Original Text

The text related to the cultural heritage 'Carlsbad Caverns National Park' has mentioned 'The Bottom' in the following places:
Occurrence Sentence Text Source
Stones were tossed into it, but no sound of the stones striking the bottom was heard.
Later exploration revealed the bottom was about 140 feet (43xc2xa0m) deep and covered with soft dirt.
The stones made no sound when they struck the bottom because they were lodged in the soft soil.