From Wood and Kienle (1990)
[1]: "Devils Desk is a volcanic neck of a former stratovolcano now completely surrounded by Hook Glacier. Total relief from the top of Hook Glacier to the top of Devils Desk is ~450 m. Extensive erosion has removed most of the stratovolcano. Three radial dikes (now exposed as ridges) extend outward from the Desk toward the east." Hildreth and others (2003)
[2] dated a block of lava from the southwest face of Devils Desk at 245 +/- 42 ka.