852 Subsurface Geologic Methods 



Structure 



Showings and oil and gas production from "sub-Trenton" rocks 



Oil and gas production from Middle Ordovician rocks 



Other areas of Trenton production 



Oil and gas possibilities 



Figure 1. Outcrop areas of Cambrian and Ordovician rocks, and major struc- 

 tural features around the Michigan Basin. Areas of oil and gas pro- 

 duction from the Trenton limestone and older rocks are also shown. 



Figure 2. Thickness of Upper Cambrian and Lower Ordovician rocks in the 

 Michigan Basin. 



Figure 3. Subsurface section from southeastern Michigan to northeastern Ohio 

 showing lithologic characteristics and thickness of Cambrian, Lower 

 and Middle Ordovician rocks. 



Figure 4. Subsurface section from northeastern Indiana to northeastern Ohio 

 showing lithologic characteristics and thickness of Cambrian, Lower 

 and Middle Ordovician rocks. 



Figure 5. Lithofacies map of Middle Ordovician rocks. 



Figure 6. Thickness of Middle Ordovician rocks in the Michigan Basin. 



Figure 7. Thickness of Upper Ordovician rocks in the Michigan Basin. 



Figure 8. Contours on top of pre-Cam.brian. 



Figure 9. Contours on top of Trenton limestone. 



Table 1. Wells, with depths to top of Ordovician and older rocks determined 

 from mounted drill cuttings (depths and elevations in feet.) 



Table 2. Wells with oil and gas production below Middle Ordovician rocks. 



Subsurface Trenton and Sub-Trenton Rocks in Ohio, New York, 

 Pennsylvania, and West Virginia " 

 charles r. fettke, carnegie institute of technology 

 Abstract 

 Introduction 

 Stratigraphy 

 Outcrops 



Subsurface sections 

 Stratigraphic sections 

 Correlation 



Upper Cambrian or Croixian series 

 Lower Ordovician or Canadian series 

 Middle Ordovician or Champlainian series 

 Unconformity at the base of the Middle Ordovician 

 Structure 



Oil and gas possibilities 

 Trenton 

 Sub-Trenton 

 Figure I. Regional structural map contoured on the top of the Trenton limestone. 

 Figure 2. Correlation chart of the Middle and Lower Ordovician and Cambrian 



formations around the northern rim of the Appalachian Basin. 

 Figure 3. Stratigraphic section across the northern part of the Appalachian Basin 



from northern Ohio to south-central New York. 

 Figure 4. Stratigraphic section along the 79th meridian of longitude. 

 Figure 5. Stratigraphic section along the 82nd meridian and across central Ohio. 

 Figure 6. Thickness map of Middle Ordovician limestones in the northern part of 



the Appalachian Basin. 

 Figure 7. Thickness map of Upper Ordovician series in the northern part of the 

 Appalachian Basin. 



Subsurface Lower Cretaceous Formations of South Texas" 

 ralph w. imlay, united states geological survey 

 Abstract 

 Introduction 



" Am. Assoc. Petroleum Geologists Bull., vol. 32, no. 8, pp. 1457-92, Aug. 1948. 

 " Am. Assoc. Petroleum Geologists Bull., vol. 29, no. 10, pp. 1416-1469, Oct. 1945. 



