"I don't see anybody," Tiffany said nervously, peering into the almost impenetrable shadows that lined the access.

Which did not do anything to explain why he stood rooted to that spot for so long afterward, gazing north into the dense, impenetrable shadows.

There was nothing to see but time-worn stone and impenetrable shadows.

The whole street was dark, full of impenetrable shadows.

There was just enough light to create impenetrable, purple-black shadows on all sides.

Gently she led him to the edge of the road where the tall poplar-trees cast long, impenetrable shadows.

The light was too weak to reach very far, and the tunnel seemed layered with impenetrable shadows.

She whirled and faced a wall of impenetrable shadow.

Ahead, the draw was a mass of impenetrable shadows.

(further and S. of the Mountain) is mantled in impenetrable shadow.