7 65 17CC 0 0 145.00 145.10 S 51 1 S RT VOLCANIC SANDSTONE 2 S % FRAGMENTS OF CHERT ARE COMMONLY IN CONTACT WITH 3 S % MUDSTONES AND COARSE SANDSTONES; 4 S TEX COARSE-GRAINED* 5 G % CONTAINS GRAINS UP TO 3MM DIAMETER.GRAINS BETWEEN 6 G % APPROX 0.7 AND 2MM ARE MOST ABUNDANT.THEY ARE 7 G % FRAGMENTS OF ALTERED VOLCANIC ROCK,AS WELL AS 8 G % LESSER AMOUNTS OF FORAMS,FISH REMAINS,AND 9 G % MUDSTONES,ALL SET IN AN OPALINE(LOCALLY 10 G % CHALCEDONIC OR CALCAREOUS)GROUNDMASS.TO SHOW 11 G % SOMETHING OF THE GREAT DIVERSITY OF LITHOLOGIC 12 G % TYPES PRESENT AS SAND GRAINS,THE FOLLOWING LIST IS 13 G % OF GRAINS INTERCEPTED ON A TRAVERSE ACROSS THIS 14 G % THIN SECTION: FINELY LAMINATED PRE-EXISTING TUFF, 15 G % PALAGONITE,SILICIFIED LITHIC TUFF,ALTERED VOLCANIC 16 G % (HEMATITE,CLAY,CHLORITE,MAGNETITE?),LITHIC GRAIN- 17 G % NOW ZEOLITE, PARTLY DEVITRIFIED GLASS,PALAGONITE, 18 G % FRAGMENT OF BANDED CHERT(CHALCEDONY IN COLLOFORM 19 G % LAYERS LESS THAN .01MM THICK),LITHIC GRAIN-NOW 20 G % ZEOLITE AND CHALCEDONY,GLASS PARTLY DEVITRIFIED TO 21 G % MOSAIC OPAL AND CLAY,ALTERED VOLCANIC(BASTITE 22 G % SERPENTINE AND CLAY),FORAM WITH PRISMATIC CALCITE 23 G % WALLS("PSEUDOISOGYRE"),VOLCANIC GRAIN WITH PLAG 24 G % TWIN ONLY PARTLY ALTERED TO CLAY,VERY FINE GRAINED 25 G % CHALCEDONY AROUND IRREGULAR TO ROUNDED CLAY MASSES 26 G % (PROBABLY ORIGINALLY VESICULAR GLASS),ALTERED 27 G % VOLCANIC(BASTITE SERPENTINE,CLAY AND IDDINGSITE), 28 G % SILICIFIED MUDSTONE,SILICIFIED VOLCANIC WITH 29 G % RADIAL CHALCEDONY IN VESICLE,FORAM WITH PRISMATIC 30 G % CALCITE WALL,LARGE AGGREGATE GRAIN OF EARLIER 31 G % SILICIFIED VOLCANIC AND PALAGONITE GRAINS,EACH 32 G % RIMMED BY COLLOFORM CHALCEDONY THAT CEMENTS THEM 33 G % TO EACH OTHER-BOTH CEMENT AND GRAINS NOW FRACTURED 34 G % LIKE IN MINIATURE A "POLYMICTIC CONGLOMERATIC 35 G % QUARTZITE",SILICIFIED AND CLAYEY VOLCANIC GLASS, 36 G % PALAGONITE,ETC. ALSO SEEN,BUT NOT ON THIS RANDOM 37 G % TRAVERSE,WERE SUCH GRAINS AS: COLLOFORM PALAGONITE 38 G % AROUND VESICLES,PALAGONITE GRAINS WITHIN 39 G % SILICIFIED MUDSTONE GRAINS,FORAMS WITH WALLS OF 40 G % MOSAIC CALCITE,FORAMS WITH CHAMBERS CONTAINING 41 G % MICRITE,MICRITE GRAINS,ALTERED ROUNDED FELDSPAR 42 G % WITH CLAY BLADES PARALLEL TO ORIGINAL CLEAVAGE, 43 G % MUDSTONE WITH RADIOLARIAN SKELETONS SHOWING 44 G % SMALL SCALE(ABOUT .3MM)RIPPLES,LARGELY ALTERED TO 45 G % CHALCEDONY,POIKILITIC CALCITE XTLS WITH ALTERED 46 G % GLASS? AND CHALCEDONY INCLUSIONS.THIS BED IS 47 G % COMPOSED OF A VARIETY OF PRE-EXISTING PYROCLASTIC 48 G % AND ORGANIC ROCKS.PROBABLY MOST OF THE ALTERATION 49 G % OF THE VOLCANIC ROCKS TOOK PLACE BEFORE THEY WERE 50 G % ERODED AND REDEPOSITED AS THIS BED* 51