Base Cretaceous (marker) Formation

Operator-reported tops from 8,334 wells across 24 counties, median tops running 172–1,950 ft by county.

Top depth: 276 ft 887 ft

456 wells shown (sampled from 8,334)

Depth by County

County	Wells	Median Top	Typical Range	CSV
Sutton	4,372	825 ft	693–945	↓
Pecos	1,569	560 ft	378–1,378	↓
Crockett	695	675 ft	571–988	↓
Schleicher	412	804 ft	520–1,292	↓
Edwards	263	1,028 ft	930–1,200	↓
Tarrant	233	1,638 ft	1,175–1,950	↓
Cooke	185	725 ft	550–1,310	↓
Parker	105	525 ft	358–766	↓
Terrell	84	934 ft	761–1,164	↓
Irion	81	400 ft	236–500	↓
Hood	73	600 ft	325–800	↓
Johnson	58	1,678 ft	1,048–2,068	↓
Denton	46	1,350 ft	1,017–1,600	↓
Val Verde	28	856 ft	335–1,626	↓
Hill	26	1,650 ft	1,425–1,675	↓
Sterling	22	350 ft	253–412	↓
Grayson	21	1,807 ft	1,600–2,160	↓
Tom Green	21	221 ft	194–375	↓
Ellis	8	1,950 ft	1,928–2,180	↓
Ector	8	172 ft	140–226	↓
Upton	7	434 ft	311–570	↓
Cochran	6	412 ft	400–2,296	↓
Erath	6	275 ft	225–350	↓
Kimble	5	387 ft	387–483	↓

Counties with fewer than 5 wells omitted. Depths are measured depth as filed; typical range is the 10th–90th percentile of reported tops — raw filings contain occasional typo depths, so extremes are not shown.