described at URL: https://www.flickr.com/photos/jsjgeology/23712775298/ operator: Flickr URL: https://live.staticflickr.com/4454/23712775298_f9336d083e_o.jpg...
described at URL: https://www.flickr.com/photos/jsjgeology/36854841444/ operator: Flickr URL: https://live.staticflickr.com/4509/36854841444_cb6ed83acd_o.jpg...
DescriptionBlack porphyritic dacite (upper Holocene, 14 May 1915; Devastated Area, Lassen Volcano National Park, California, USA) 7.jpg English: This is...