Each zip file is about 200 megabytes. It unzips to an arc/info grid (named e.g. m41116) covering a one-degree block. Some unzip to a workspace of the same name. Others unzip to the current directory, potentially causing grief and pain. As the data is in UTM (zone 10 and zone 11), the block overlap slightly. This is public-domain USGS data assembled by the BLM.
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