_ DESCRIPTION AND NAMING OF SEDIMENTARY ROCKS 663 
Texture granular-fragmental. Constituents calcite 50 per cent; 
quartz 333 per cent; siderite 10 per cent; small amounts of mag- 
netite, ilmenite, zircon, muscovite, Blnucenite as accessories, and 
limonite as alteration product. 
Calcite o.2mm., giving evidence of recrystallization; also as 
rods. Glauconite aggregates about 0.5 mm., much replaced by 
limonite. Limonite also edges siderite rhombs. Quartz 0.04 mm., 
near-angular to subrounded. 
Classed: arenaceous trilobitic medium-grained glauconite- 
limestone. 
Wy 13: Same locality as Wy 16, 260 ft. above granite. 
Description of hand specimen: Limestone, thin-bedded, blue- 
gray, subsoft but brittle, the 1-in. layers separated by micaceous 
shale; subvitreous luster, black-specked, seemingly unfossiliferous. 
Texture granular-fragmental. Constituents calcite 50 per cent; 
quartz 25 per cent; glauconite 20 per cent; small amounts of 
ilmenite, zircon, apatite as accessories. Liquid and gas inclusions 
In quartz. Cement calcite. 
Quartz o.t mm., angular. Calcite grains 0.5 mm.; main occur- 
rence as rods. 
Classed: arenaceous trilobitic medium-grained glauconite- 
limestone. 
Wy 57: Same locality as Wy So, 4 ft. above that horizon. 
Description of hand specimen: Sandstone, massive, gray-green 
with irregular-bedded effect due to light-colored stretches between 
dark-brown bands, with parallel orientation of Dicellomus shells; 
soft, coarse-grained, calcareous, particularly toward top, glau- 
conitic, dull to subvitreous luster. Cross-bedded. 
Texture granular-fragmental. Constituents quartz 80 per cent; 
glauconite ro per cent; calcite 5 per cent; small amounts of biotite, 
muscovite (?), apatite as accessories. Cement calcite. Liquid 
and sas inclusions in quartz. 
Quartz o.2 to 0.5 mm., subrounded to oval, at times subhex- 
agonal. Glauconite seldom related to shell interiors, not even in 
an admirable cross-section with quartz fragments in shell and 
cemented by calcite and limonite. 
Classed: glauconitic medium-grained sandstone. 
