The explorers went deep into the cavern in the mountain.    From LearnThat.org. 

"Where is his mountain cavern, and how can I reach it?".    From Wordnik.com.  [Folk Tales From Many Lands] Reference

Be careful, now, the floor of this cavern is several feet below the opening.    From Wordnik.com.  [The Hidden Hand] Reference

The dome of one cavern is three hundred and fifty-five feet from floor to roof.    From Wordnik.com.  [The Golden Chersonese and the Way Thither] Reference

"Go to my mountain cavern," he commanded, "and bring me a sack of my buried treasure.".    From Wordnik.com.  [Folk Tales From Many Lands] Reference

The conversation overheard by Rollo in the cavern was a trick.    From Wordnik.com.  [The Billow and the Rock] Reference

Among the articles found in the cavern was a rusty old musket.    From Wordnik.com.  [Captain Mugford Our Salt and Fresh Water Tutors] Reference

Near the cavern was a precipice, with a glen or gully below it.    From Wordnik.com.  [Dick Onslow Among the Redskins] Reference

Discovered in 1940, the cavern is a UNESCO World Heritage site.    From Wordnik.com.  [Central Florida News 13 - Latest Headlines] Reference

The back half of the cavern was a wall of pocked volcanic rock.    From Wordnik.com.  [Ice Hunt]

My cavern is the best bat observation area anyone has ever discovered.    From Wordnik.com.  [Going Mutant] Reference

The cavern was a natural one, but man had made of it a not impossible habitation.    From Wordnik.com.  [Ruth Fielding on the St. Lawrence The Queer Old Man of the Thousand Islands] Reference

The cavern was a formless place where colors and shapes kept wavering and changing.    From Wordnik.com.  [Night Arrant]

The center of the cavern was a lake, taking up something more than half of its area.    From Wordnik.com.  [Under the Andes] Reference

At the entrance to the cavern were the remaining su-chi, lurching into the sunlight.    From Wordnik.com.  [The Brothers' War]

At the centre of the cavern was a long table of pine, around which were fifty chairs.    From Wordnik.com.  [The Hawk Eternal]

In the very middle of the cavern was a little lake, shaped in the same proportion as the floor.    From Wordnik.com.  [Hunters Out of Space] Reference

The sides of the cavern were a veritable maze of boulders, sloping ledges, and narrow crevices.    From Wordnik.com.  [Under the Andes] Reference

Within the cavern was a sort of dairy, with great piles of cheeses, and vessels brimming with whey.    From Wordnik.com.  [Stories from the Odyssey] Reference

The dwarf who entered the cavern was the most repulsive example of the derro race Flint had ever seen.    From Wordnik.com.  [Flint the King]

The very first piece of equipment to reach the floor Of the cavern was the portable Honda EM500 generator.    From Wordnik.com.  [The Seventh Scroll]

Somewhere in the cavern were the priests, the Teeth of Gwahlur, and perhaps a clue to the fate of Muriela.    From Wordnik.com.  [The Conquering Sword of Conan]

The cavern, which is so named from its limited extent as compared with Mammoth, is a mile from the station.    From Wordnik.com.  [Archeological Investigations Bureau of American Ethnology, Bulletin 76] Reference

"Some kind of cavern," Greg said, looking around while Bill whimpered softly.    From Wordnik.com.  [Analog Science Fiction and Fact]

It was a kind of cavern, caused by the falling together of two pieces of ice, with double issue.    From Wordnik.com.  [International Weekly Miscellany - Volume 1, No. 5, July 29, 1850] Reference

Russia's Amber room may be in German cavern.    From Wordnik.com.  [RIA Novosti] Reference

Two inclined rocks form a kind of cavern, which affords.    From Wordnik.com.  [Personal Narrative of Travels to the Equinoctial Regions of America, During the Year 1799-1804 — Volume 1] Reference

"It is called the cavern of the dwarfs, your lordship, and very well named too.    From Wordnik.com.  [Honey-Bee 1911] Reference

Two inclined rocks form a kind of cavern, which affords a shelter from the winds.    From Wordnik.com.  [Travels to the Equinoctial Regions of America] Reference

When we ran into the dingy cavern which is Amiens station I seemed to note a new excitement.    From Wordnik.com.  [Mr. Standfast] Reference

A kind of cavern opened up at the intersection of several tunnels, filled with a sourceless, pale green light.    From Wordnik.com.  [NZ On Screen] Reference

A kind of cavern, are still called the house or dwelling of the great forefather of the Tamanacs.    From Wordnik.com.  [Personal Narrative of Travels to the Equinoctial Regions of America, During the Year 1799-1804 — Volume 2] Reference

Vibrations of a cavern a mile beneath silver willows.    From Wordnik.com.  [Silver Spring to Phoenix] Reference

Sleeping alone, Cody felt void, his interior liquid and cold, like an icy cavern.    From Wordnik.com.  [misshaped planet] Reference

But, no matter how deeply I felt through the cavern of sheets, I couldn't find her.    From Wordnik.com.  [The Movement of Strings] Reference

 The lobby is a great cavern of red and thumps with heavy bass music, like a model of a human heart.    From Wordnik.com.  [One Last Thing Before You Go] Reference