No	Name	Flown By	Date Flown	Spacing	Dir	Altitude	LnMi	Datum	Publication
3143A	Upper Michigan East	LKB	10/78-11/78	1 mi.	N-S	500 AG	2435	IGRF75, 59000	OF79-833
3143B	Upper Michigan West	LKB	09/78-11/78	2 mi.	E-W	500 AG	680	IGRF75, 59000	OF79-833
3176A	Michigan Peninsula East	Geodata	05/79-07/79	2 mi.	N-S	500 AG	890	IGRF75	OF80-830
3176B	Michigan Peninsula West	Geodata	05/79-07/79	1 mi.	N-S	500 AG	1295	IGRF75	OF80-830
4033	Limestone Mountain	HighLife	10/80	0.5 mi.	N-S	400 AG	30	IGRF75	OF83-195
4036A	Jacobsville Contact South	HighLife	10/80	0.25-0.5 mi.	var.	400 AG	924	IGRF75	OF83-195
4036B	Jacobsville Contact North	HighLife	10/80	0.25-0.5 mi.	N-S	400 AG	188	IGRF75	OF83-195
4221C	Northeast Wisconsin	HighSense	10/98-02/99	0.5 mi.	N-S	1000 AG	12000	IGRF95	OF99-527
4221D	Wisconsin Tie Lines	HighSense	09/98-02/99	Var.	E-W	1000 AG	1425	IGRF95	OF99-527

Description of Table

No.: Internal USGS identification number
Name: Internal project name (not always the name used in publication title)
Flown By: Company or government agency who flew the original survey
Spacing and Dir.: Primary flight-line spacing and primary flight-line direction
Altitude: Primary flight altitude in feet; B = barometric elevation, AG = above ground draped over topography
LnMi.: Approximate total of line miles flown for this survey
Datum: Indicates if a regional field was removed and, if it could be determined, the base value removed. Total field = no regional was removed. Arb. (arbitrary) datum = the base value removed was not stated on the map or in survey reports.
Publication: Brief publication reference*. USGS publications are listed as: Open-File reports = OFxx-yyyy where xx is the publication year, Bulletins and Professional Papers = B-yyyy or P-yyyy, Geophysical Maps = GP-yyyy, Miscellaneous Field Studies Maps = MF-yyyy, Miscellaneous Investigations Maps = I-yyyy.

*For a full reference for USGS publications see: http://library.usgs.gov/