D.A. Grisafe 2002 Samples of the Tongue River Sandstone, collected from the top of Steamboat Butte in central Montana, were treated with an ethyl silicate solution. The samples showed a large increase in compressive strength and freeze-thaw resistance, relative to untreated samples, and indicates the treatment(s) significantly consolidate(s) the stone, thus providing a method to increase the lifetime of the petroglyphs carved onto the stone. application/pdf 10.1080/2052546.2002.11932112 en Taylor & Francis Potential preservation of native American petroglyphs at Steamboat Butte, Montana, using ethyl silicate solution treatments article