The call-numbered books (monographs) in the Geology Library are located in both the Reading Room and the South Mudd Room.
The Reading Room (North Mudd Reading Room) has call-numbers G to GF.
The South Mudd (Geology South Mudd room I books) houses some Q, QB-QH, as well as some T and Z call-number ranges.
As you enter the Geology Library, heading west down the hall, you will see on your left an open hallway door. Follow this hallway south, down the few steps, and you will see the call-numbered books for the South Mudd room.
