Explanation of Abbreviations and Symbols

N, North;
S, South;
E, East;
W, West;
C, Consolidated;
Cen, Central.
Fields located in two or more counties have county names listed in order of oil discovery.

PC, Precambrian;
CAM, Cambrian;
ORD, Ordovician;
SHK, Shakopee;
STP, St. Peter;
TRN, Trenton;
SIL, Silurian;
DEV, Devonian;
DVS, Devonian-Silurian;
MIS, Mississippian;
PEN, Pennsylvanian.

D, dolomite;
DS, sandy dolomite;
L, limestone;
LS, sandy limestone;
OL, oolitic limestone;
s, sandstone

A, anticline;
C, stratigraphic trap;
D, dome;
F, faulting;
H, strata horizontal or nearly horizontal;
L, lens;
M, monocline;
N, nose;
R, reef;
T, terrace;
U, unconformity.
Combinations of the letters are used when more than one factor applies.