The Skagit Valley occurrence is underlain by granite of the Oligocene Chilliwack batholith.

At present, Quarry Pacific Industries shapes square blocks from the boulder train of an ancient rock slide. Blocks are spread throughout the flat valley bottom. The source is probably from massive outcrops on the west side of the valley. There are two granite phases - attractive pink, quite homogeneous which is intruding grey greenish coloured rock more susceptible to weathering. Rock is processed by Margranite Industry Inc. into granite tile in Surrey. Production statistics are not available.