0001005477-97-000501 SC 13G/A 1 19970218 NASD GUARDIAN INVESTOR SERVICES CORP. GUARDIAN LIFE INSURANCE CO OF AMERICA THE GUARDIAN EMPLOYEE INCENTIVE SAVINGS PLAN THE GUARDIAN LIFE INSURANCE COMPANY OF AMERICA THE GUARDIAN PARK AVENUE FUND THE GUARDIAN STOCK FUND, INC. THE GUARDIAN-MASTER PENSION TRUST BASIN EXPLORATION INC 0000827795 1311 841143307 DE 1231 SC 13G/A 34 005-42629 97537329 370 SEVENTEENTH ST STE 1800 DENVER CO 80202 3036858000 370 SEVENTEENTH STREET SUITE 1800 DENVER CO 80202 GUARDIAN LIFE INSURANCE CO OF AMERICA 0000901849 061116976 NY SC 13G/A 201 PARK AVENUE SOUTH AREA 9C NEW YORK NY 10003 2125988359 SC 13G/A 1 000100547797000501-001-seq1-sc-13g-a.txt SCHEDULE 13G/A FOR BASIN EXPLORATION, INC.