Read "Sphinx And Medusa" at The Eldritch Dark:
This is a wicked little poem, wherein Clark Ashton Smith (CAS) has combined his love of mythology with a doomed vision of mankind's ultimate fate. The closing lines are especially effective:
When from the spaces of Eternity,
Silence, a rigorous Medusa, turns
On the lost world the stress of her regard.
The use of commas in the middle quoted line (line 13 in the complete poem) creates pauses which encourage the reader to imagine Silence, personified as Medusa, slowly turning and gazing with "the stress of her regard." Given what happens to those who make eye contact with one of the Gorgons, things do not bode well for our "lost world"!