HOUSTON COUNTY. 319 



are principally covered with gray sand. Probably the larger portion may be 

 classed as sandy, although considerable areas exist of black, red, and gray 

 loams. With the exception of soils resulting directly from the weathering 

 of the greensand marls themselves, which are the very best of soils, the sandy 

 soils fertilized with the greensand are best adapted to fruit culture. 



IRON ORE AREAS. 



The only iron ore areas so far examined in this county are found in a series 

 of oval shaped hills which extend in a northeast and southwest direction 

 across the county north of Crockett. 



GENERAL GEOLOGY. 



In this county, so far as our investigations have shown, we have repre- 

 sented only strata of the Tertiary and Quaternary age. 

 The general section is: 



QUATERNARY Orange Sands. 



( Iron Ores. 



TERTIARY •] Fayette Beds. 



( Timber Belt Beds. 



QUATERNARY. 



The gray sands, the mottled and sandy clays, and the yellow sands, which 

 in so many places are the surface formation of the county, are of Quaternary 

 age. Too little study has been done on them as yet to enable us to fully define 

 them, or to distinguish in every instance between these and some beds of 

 very similar appearance and composition which are earlier. 



THE IRON ORES. 



It is very possible also that a part of the deposits of iron ore which are 

 found capping the hills or scattered along their sides belong to the same 

 period Part of them might possibly be assigned to the Fayette beds, making 

 them the equivalent of the sandstones of that formation. The grounds for 

 such a reference are, however, seemingly entirely insufficient, and unless future 

 investigations add stronger reasons for this correlation than have yet been 

 brought forward it will hardly be tenable. The principal reason for even 

 suggesting such a correlation is the occurrence of a belt of ferruginous ma- 

 terial at the contact of the clays and sands of these beds which closely resem- 

 bles some of the conglomerates and siliceous ores of this region. The greater 

 part of them are probably remnants of the Tertiary deposition. 



