Pacific–Farallon Ridge
The Pacific-Farallon Ridge was a spreading ridge during the Late Cretaceous that extended 10,000 km in length and separated the Pacific Plate to the west and the Farallon Plate to the east. It ran south from the Pacific-Farallon-Kula triple junction at 51°N to the Pacific-Farallon-Antarctic triple junction at 43°S. As the Farallon Plate subducted obliquely under the North American Plate, the Pacific-Farallon Ridge approached and eventually made contact with the North American Plate about 30 million years ago.