
Key to Grain Sizes and Types
s = sand
si = silt
m = mud
vf = very fine
f = fine
md = medium
p = pebble
g = gravel
tuff. = tuffaceous
Descriptive Abbreviations:
d. silt lam. = discontinuous silt laminations
in massive mud
filled crack? = vertical planar features
interpreted as mud filled cracks
Key to Color Codes:
7.5YR5/4 = brown
7.5YR6/3 = light brown
7.5YR6/4 = light brown
10YR4/3 = brown
10YR5/4 = yellowish brown
10YR6/2 = light brownish grey
10YR6/3 = pale brown
10YR6/4 = light yellowish brown
10YR7/2 = light grey
10YR7/3 = very pale brown
2.5Y6/2 = light brownish grey
2.5Y6/3 = light yellowish brown
2.5Y7/2 = light grey
2.5Y7/3 = light yellow
5Y6/3 = pale olive
5Y7/2 = light grey
5Y7/3 = pale yellow
5GY5/1 = greenish grey
This page is <https://pubs.usgs.gov/openfile/of95-001/8-append/pod_key.html>
Maintained by Eastern Publications Group Web Team
Last modified 28-Feb-2001