Image from http://pubs.usgs.gov/gip/acidrain/5.html The USGS has noted the effect of acid rain on limestone decorations on public buildings. Note the rounding of formerly sharp details. |
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Image from http://pubs.usgs.gov/gip/acidrain/5.html The USGS has noted the effect of acid rain on limestone decorations on public buildings. Note the rounding of formerly sharp details. |