Specimen Number45-4-007Alternate Number7CommentsWeakly to moderately welded ash-flow tuff, part of oldest volcanic sequence, dated at 38 my.In Teaching CollectionNoMineral(s)quartzfeldsparbiotiteclayRock Namerhyolite tuffDistrictThomas RangeMineregional sampleDeposit TypeEpithermalDonated ByUniversity of Wisconsin-Madison Department of Geoscience