PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT PUBLICATION_DATE = 2009-11-15 NOTE = "Sample description" END_OBJECT = TEXT END Unit 4 (reference, Deschutes_Formation_strat.jpg). Massive lahar with some discrete layering. Sequence from bottom to top displays poorly-sorted layers, massive unit, oxidized layers, crossbeds and vesicular sequence. High-level Description: Coarse/fine-grained, incipiently-layered sequence at the bottom of Unit 4, a grey, massive lahar. Texture Grain morphology and appearance: Rough, rubbly, sub-angular to sub-round tephra grains layered in a coarse- to fine-grained alternating sequence. Grain size and sorting: Poorly-sorted alternating coarse- to fine-grained layers, with fine grains averaging 0.25 mm and coarse grains averaging 0.67 mm in diameter. Grain fabric: Polymodal. Sediment structure: Parallel lamination. Color: Black and buff grains, with some white and a few red grains mixed.