the mountain prison

"In Pierre the mountain replaces the whale as the central image of materiality, and rocks and stones rather than lines and ropes define the threatening environment in which man is imprisoned.  ...the mountain in Pierre is the mute, material other...."
--Edgar A. Dryden, Melville's Thematics of Form

"Pierre also seems to resemble Enceladus with the mountain thrown down upon him. "
--Brian Higgins and Hershel Parker, Reading Melville's Pierre

 March 1853, Scenes Beyond the Western Border:

My watch is lonely and fearfully silent;— every where a voiceless desert, and mountains like prison-walls; and thus—

"I live and die unheard
With a most voiceless thought."

Scenes Beyond the Western Border
Southern Literary Messenger (March 1853): 157

Revised as follows in Scenes and Adventures in the Army (386-7):

Are these wild mountains impassable barriers, that must prison all sympathy from earthly communion? In vain, in vain! Dull tyrant space wears its stoniest frown;—there is no whisper of life or motion in the air; the elements but echo a human sigh; and thus,

"I live and die unheard
With a most voiceless thought." 

The quoted poetry is from Byron, naturally:
Canto III of  
Childe Harold's Pilgrimage.