Mary E. J. Colter’s ‘Geologic Fireplace’

Architect and decorator Mary E. J. Colter (1869-1958) worked off-and-on at the Grand Canyon for four decades while employed by hospitality company Fred Harvey. Attracting and entertaining guests was part of her brief, but she often achieved this with an educational flourish. In her design for the south rim’s Bright Angel Lodge, Colter integrated the geology of the Grand Canyon into the lounge’s fireplace. The rocks used in its construction were gathered from different strata of the canyon and packed out by mules led by trail guide Ed Cummings.

Colter’s goal was to reference the geology of the canyon to create an “authentic and therefore interesting” fireplace for guests. To achieve scientific accuracy, she relied on park naturalist Edwin McKee. “I know the design I want but depend entirely on you for the geology,” she wrote to him in 1935, when she also asked McKee to review the rocks collected by Cummings. “You know I am not trying to show every strata in every part of the whole canyon, - only those that occur either on the Bright Angel or the South Rim part of the Kaibab trails.”

Ranger and visitors with McKee’s geological column, 1932 (NPS)

A few years earlier and two miles away, McKee had constructed a similar rock column exhibiting different strata of the canyon on the porch of what is now the Yavapai Museum of Geology. (This column was removed in 1978.) McKee later recalled of his contribution to the fireplace, “At Mary Colter’s request, I helped her work out the scale, locate appropriate rock specimens, and check for accuracy in rock thickness and positions.”

Colter's geological fireplace. (GRCA 2788 NPS/Michael Quinn, 2011)

On the hearth by the base of the fireplace are rocks worn smooth by the Colorado River at the bottom of the canyon. The National Park Service describes the rest of the rock forming the fireplace as follows:

Zoroaster Temple (brewbooks, 2011, CC BY-SA 2.0 DEED)

“The base of the fireplace consists of dark-colored Vishnu Schist. This granite-veined rock – dated at around 1.7 billion years old – forms the very basement of the North American continent. The next layer of rock represents the Grand Canyon Supergroup –sedimentary and volcanic rocks ranging in age from 800 million to 1.2 billion years old; their tilted appearance caused by the separation of ancient continents. Above the fireplace opening is a distinctive layer of flat-lying sedimentary rocks that give the Grand Canyon its “stairstep” appearance and date from half a million to 250 million years in age.

“Some of the youngest rocks are found at the top of the fireplace. That band of light-colored stone completes the geologic timeline of the Grand Canyon. Known as the Kaibab Formation, this limestone rock is a mere 270 million years old and is visible along much of the canyon’s rim.”

While McKee’s geological column undoubtedly inspired Colter’s fireplace construction, some suggest the profile of the canyon’s Zoroaster Temple inspired its shape (see photo). Since Colter’s time, the Bright Angel Lodge’s lounge has been transformed into a History Room where visitors can still admire her “Geologic Fireplace.”

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Sources:

Edwin D. McKee, letter to Virginia Grattan, March 1, 1982, 3546633, MS656, Box F2, Virginia Grattan Collection, Arizona State University.

M. E. J. Colter, letter to Eddie McKie (sic), April 1, 1935, 3546633, MS656, Box1, F1, Virginia Grattan Collection, Arizona State University.

National Park Service, “Mary Colter's Bright Angel Lodge.”