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This field trip explored the interesting landforms created by the Boring lava which came from the vent located on Rocky Butte in the Northeast part of Portland.  For GSOC readers unfamiliar with this area of Portland, Rocky Butte is a prominent landscape feature on the northeast side of Portland just south of the Portland airport and near the I-84 and I-205 interchange.  Rocky Butte was also the site of the Multnomah County jail until I-205 was opened in the 1980's.

The field trip began at the Grotto, a property owned by the Roman Catholic church.  The Grotto is located off NE Sandy Boulevard, just east of the intersection with 82nd Avenue.  The site was used as a quarry by the Union Pacific Railroad from the late 1800's until it was purchased by Father Ambrose Mayer in 1923.  The property was dedicated the following year as The  National Sanctuary of our Sorrowful Mother by Portland Archbishop Alexander Christie.

The Grotto is hewn from the base of the Boring lava basalt cliff, which exceeds 100 feet and divides the property.  The Grotto shrine is a statuary carved in Italy from pristine white Carrara marble.  The shrine stands in sharp contrast to the gray, moss covered, dripping basalt in which it is framed.

The shrine at the Grotto in NE Portland.

At the base of the cliff near the Grotto are also a collection of buildings including a very fine sanctuary, faced in Boring lava.  Imported stone also lines the doorways and the sanctuary interior.  An elevator transported the group to the top of the cliff, which contained a very fine strolling garden and inspiring meditation chapel poised at the brink of the cliff with a breathtaking view to the north.

The elevator at the Grotto climbs about 100 feet  to the top of Rocky Butte.

The group then visited the quarry site itself, just to the east of the sanctuary.  Taylor pointed out the possible position of a lava tube in the side of the cliff.

The group next drove to the cliff top on the way up the northern approach of Rocky Butte, and looked down on the quarry site.  The cliff appears so much taller when one is standing on the brink!  The group passed the old Military school on the way up the hill, which was founded in 1878 by J. W. Hill.  He and his students persuaded Multnomah County to construct the road to the top which has a fabulous 270 degree view of the area.

On the way up the hill the group also observed rounded boulders which were probably brought by the Ice Age Floods.  Some shaped stonework also lines the road, and the viewpoint at the top is a veritable fortress of stonework, built by the WPA in the 1930's.

Barbara Hawxhurst, President of the Rocky Butte Preservation Society, addressed the field trip group at the windy summit.  The Preservation Society is responsible for restoration efforts which have greatly enhanced the park in recent years.  The light fixtures one sees on the pilasters are recent additions by the Preservation Society – they have been specially designed to match the period of the stonework.

Barbara Hawxhurst of the Rocky Butte Preservation Society  addresses the group at the viewpoint at the top of Rocky Butte.

The field trip departed the summit by the western route (with the hairpin tunnel!) and visited the huge depression on the western flank which Taylor theorizes is a plunge pool from the Ice Age Floods.

For more information on Boring Lava, refer to the December 2000 issue of the Geological Newsletter, "The Not-So-Boring Volcanics", or refer to these pages of the USGS/Cascades Volcano Observatory website:
http://vulcan.wr.usgs.gov/Volcanoes/Oregon/BoringLavaField/description_boring_lava.html

For additional information, check your monthly newsletter or contact Janet Rasmussen <jkayerocks@yahoo.com> (541) 753-0774