Massive Anhydrite (marker) Formation

Operator-reported tops from 4,377 wells across 30 counties, median tops running 1,735–9,248 ft by county.

Top depth: 4,587 ft 7,852 ft

168 wells shown (sampled from 4,377)

Depth by County

County	Wells	Median Top	Typical Range	CSV
Harrison	842	5,316 ft	4,541–6,138	↓
Freestone	663	7,930 ft	7,135–8,129	↓
Panola	638	4,882 ft	4,622–5,380	↓
Rusk	494	6,220 ft	5,729–6,610	↓
Smith	283	7,365 ft	7,031–7,867	↓
Gregg	242	6,526 ft	6,242–6,791	↓
Nacogdoches	197	6,766 ft	6,384–8,099	↓
Henderson	141	8,534 ft	7,472–9,276	↓
Upshur	140	6,902 ft	6,720–7,074	↓
Limestone	126	7,140 ft	6,264–7,590	↓
Shelby	112	5,132 ft	4,624–6,243	↓
Cass	78	5,626 ft	5,288–6,133	↓
Robertson	66	7,280 ft	6,872–7,773	↓
Cherokee	57	7,930 ft	7,280–8,720	↓
Marion	55	5,572 ft	4,890–6,580	↓
Anderson	44	9,065 ft	8,072–9,360	↓
Hopkins	32	7,670 ft	6,880–7,771	↓
Red River	28	3,588 ft	3,516–3,704	↓
Leon	24	8,108 ft	7,863–9,098	↓
Wood	21	7,860 ft	7,584–8,213	↓
San Augustine	18	6,796 ft	6,675–7,128	↓
Van Zandt	18	7,766 ft	7,011–8,077	↓
Navarro	14	6,215 ft	5,681–6,432	↓
Camp	8	7,299 ft	7,190–7,483	↓
Angelina	7	9,045 ft	8,831–9,168	↓
Rains	7	7,630 ft	7,470–7,908	↓
Houston	6	9,248 ft	9,017–10,478	↓
Andrews	6	1,735 ft	1,694–1,888	↓
Bowie	5	4,520 ft	4,514–4,548	↓
Franklin	5	7,126 ft	6,156–7,158	↓

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.