Photography by Roger Wade; see slideshow here
Actually, sod roofs have been used in Scandinavia and Iceland for centuries. However I was surprised to learn that Richard Neutra was doing it in the fifties in Montana. He designed it for Geography professor Nick Helburn, who maintained the cantilevered sod roof with the assistance of a built-in sprinkler system, a lawn mower and a few pet goats.
Thomas Hines writes in Architectural Digest in 2004:
The house has many features seen in Neutra’s other houses, including cantilevered roofs extending into space, the berming of service areas and storage into the sloping hillside of the site, borrowed light, expansive glass systems, the inclusion of planters inside the house, an emphasis on living space instead of privatized space and, of course, the omnipresent merging of architecture and landscape. The more unusual aspects of the project are the sod roof, the log construction and the radiant heating system.
Found in Space Invading and Materialicious
More on Green Roofs in TreeHugger:
The Ultimate Green House: Lost In Paris House by R&Sie; Architects
Are Green Roofs the New Mirrored Glass?