1. San Juan terranes- San Juan Thrust System Decatur terrane- Jurassic to early Cretaceous-An ophiolite with a younger superimposed arc. Overlying clastic marine sequence. Imbricate Fault Zone- late Cretaceous-fault slices of many different rock types– most sheared and structurally complex

2. San Juan terranes- San Juan Thrust System Constitution Formation- Jurassic to early Cretaceous- clastic sequence of volcaniclastic sediments with some ribbon cherts, and pillow lavas Garrison terrane- Permian to early Triassic– high pressure schist. Occurs as small fault slices along one of the thrust faults.

3. San Juan terranes- San Juan Thrust System Deadman Bay Terrane- Triassic to early Jurassic- ribbon cherts, pillow basalts, and limestones; Tethyan-fusulinid limstone. Turtleback Terrane- Cambrian to early Permian- plutonic complex of tonalite and gabbro. Upper unit consists of volcanic-arc with some limestones– Fusulinids are non- Tethyan.

4. San Juan terranes- External Units Haro Terrane- late Triassic to early Cretaceous- marine sandstone, conglomerates, volcaniclastic sediments Nanimo Group- late Cretaceous- marine and non-marine sandstones, conglomerates, and shale

5. San Juan terranes- Post Orogenic Unit Chuckanut Formation- Eocene– nonmarine sandstone and conglomerate