EXHIBIT 23.1 INDEPENDENT AUDITORS' CONSENT We consent to the incorporation by reference in Registration Statement No. 333-88712 on Form S-3 and Nos. 033-61850, 333-30055, 333-58273 and 333-35352 on Form S-8 of St. Mary Land & Exploration Company of our report dated February 19, 2003, related to the consolidated financial statements of St. Mary Land & Exploration Company as of and for the year ended December 31, 2002, appearing in this Annual Report on Form 10-K of St. Mary for the year ended December 31, 2002. /s/ DELIOTTE & TOUCHE LLP Denver, Colorado, March 12, 2003