English: Rocks from the Bishop Tuff, an ignimbrite tuff from Owens River Gorge, California. On the left, a rock from the latter stages of the eruption and the top of the deposit; note large grey, oval pumice fragments. On the right, a rock from the earlier part of the eruption and the bottom of the deposit; note dark, flat fiamme (squished pumice) and apparent increase in phenocrysts, though the compression that caused the fiamme most likely compressed the matrix of the tuff, increasing the apparent abundance of crystals, with respect to the matrix.