This document provides common symbols used on geologic maps to describe features such as the orientation of rock layers, boundaries between different rock units, folds, and faults. Key symbols include strike and dip symbols to show the angle and direction of inclined rock strata, lines and patterns to represent contacts between rock units, hachure patterns for the shape and plunge of folds, and various fault symbols indicating normal, strike-slip, and reverse faults.

1. Common Geologic Map Symbols
Describing orientation of geologlc features wtth strike and dip
~---
dip angle strike
& direction direction
vertical beds
tbeds Inclined
straight up
horlzonal beds
L36strata Inclined ffi nat-ll/lno
I at an anole W strata
+
basin
Rock Unit Boundaries - contacts between rock units
of different agea and/or different composition
- - contact certain
------ contact mrerred
FOLDS
++
anticline syncline
plunging folds
plunging
anticfine
+ arrow 11oln1s In
rold dip !llrectlon
•..••con111cts lnlerred beneath
sedimentarycover
FAULTS
normal fault u
/ ---:::7 honglng -11 down D
u Is on Ille up11ne11
side(foot wall)
D Is on Ille
down-dro1111ed sJlle
(IUlhQlno Wall)
strlke-sllp fault
reverse fault
hanging wall up
roocwalldo',,n
__,),.
~
hairarrows
show direction
orraunmotion
e • e e
triangles on
upper plate
Oianglng wall)
• ♦ ft.
triangles on
upper plate