Richard B. Phelps, a Maryland-native, established and ran his own stonecutting company, R.B. Phelps Stone Co., out of offices at 2501 Ninth St. N.E., Washington, D.C. According to the letterhead on correspondence from Phelps to Dumbarton Oaks, he had been in business for "Over half century continuous service under one management" by the 1950s, and R.B. Phelps Stone Company were the "oldest cut stone contractors in Washington." As a result of being in business for so much of the 20th century, Phelps Co. provided apprenticeships to many local stonecutters over the years.
References:
1930 United States Census (Population Schedule), Washington, Washington, District of Columbia; p. 4B, Line 52, Richard B. Phelps household; digital images, Ancestry.com (http://ancestry.com, accessed August 15, 2014); citing NARA microfilm publication T626, roll 303.
Garden Archives Correspondence.
"Dennis Rude." Linkedin.com. Accessed August 15, 2014. http://www.linkedin.com/pub/dennis-rude/a/81b/130
"Marion Ritchie Jr." Washington Post. January 15, 2014. http://www.legacy.com/obituaries/washingtonpost/obituary.aspx?pid=169104115
“Titanic Memorial, (sculpture).” Smithsonian American Art Museum Art Inventories Catalog. Accessed August 15, 2014. http://archive.today/FiFD