696 A. F. FOERSTE 



Cretaceous. The exposure at Coffee Landing is typical for the 

 Tennessee beds. Silicified trunks of trees are not uncommon. 

 One, 6 feet long and 2 feet in diameter, occurred in the sand 

 directly above the Glenkirk limestone at the Welch or Maddox 

 mill on Horse Creek. Another was found near Lutts, beyond 

 the post-ofifice, on the road to Waterloo. The locality is called 

 Pin Hook Hill, and lies between Rutherford and Horse Creeks. 

 A third trunk is seen on the Jack Martin farm, about seven miles 

 north of Cypress Inn and five miles south of Victory, on the 

 headwaters of Weatherford fork of Indian Creek. The trunk is 

 found in the hollow in the field below the Martin house. The 

 locality is fully twenty miles east of the Tennessee River. It 

 has been suggested that the Gulf of Mexico once extended much 

 farther north than at present, reaching the southern part of Illi- 

 nois and covering southeastern Missouri. If the Coffee sand 

 was deposited off its shores, the Gulf, during early Cretaceous 

 times, must have extended east of the Tennessee River, at least in 

 the southern part of Tennessee, in parts of Wayne and Hardin 

 counties. 



G. THE IRON ORE GRAVELS. 



In western Tennessee, in the area lying between the Great 

 Central Basin and the Tennessee River, the paleozoic rocks are 

 usually overlaid by a great mass of sands and gravels, often 

 cemented by ferruginous material. Sometimes the ferruginous 

 material is in sufficient quantity to prove valuable as an iron ore. 

 Thirty-five furnaces were in operation before the war, and the 

 ore is still mined at a number of localities. The branches of 

 railroad from Dickson to Mannie, from Summertown to Napier, 

 and from Iron City to Pinckney owe their existence to the pres- 

 ence, at their terminals and at various points along the line, of 

 ferruginous gravels, sufficiently rich in iron ore to be mined. 

 The large furnaces at Florence and Sheffield in Alabama partly 

 depend upon this source. The ferruginous iron-ore gravels 

 extend west of the Tennessee River for a distance of ten or fif- 

 teen miles, resting upon the paleozoic rocks on all the higher 

 hills. At lower levels, where the paleozoic rocks are covered by 

 the Coffee sand, the iron-ore gravels rest upon the Coffee sand. 



