Granite Basin Dam Loop via N. Skyline Drive(edit)

The western side of the loop is a dried up riparianarea at least in the month of May. Trail is mildly rocky in spots, elevation only about 600 feet very level. The eastern loop is an ideal mountain bike trail of crushed granite. A few spots of large boulders very smooth terrain. Just after making the turn at the northeast corner. You will come to a very rocky trail on your left that goes to a spectacular set of ruins. The south facing wall of the ruins I paced off at about 230 feet. Several rooms still exist. There are also some rooms just below the main complex.