92 GEOLOGICAL SURVEY OF ALABAMA. 



T. 12 of R. 2 E., in several ridges of ferruginous material, 

 but carrying only occasional chunks of Limonite ore of no 

 economic value. From thence south-westwards it is only 

 an irony belt of chert rock. 



The Third Limonite, Horizon Shows itself first still far- 

 ther to the N. E. than either of the preceeding horizons. 

 Its first prominent exposure is on the lands of Eli Bynum in 

 S. 7, T. 11, R. 3, east. It is there an iron bearing stratum, 

 probably 40 or 50 feet thick, and carrying small chunks of 

 good limonite ore. The quantity apparently insufficient for 

 profitable mining. From there it oan be easily traced south- 

 westward for a long distance. Its exact position in the Silu- 

 rian Chert formation is not so easily defined as the preced- 

 ing horizons. There are no prominent rocks or ledges here 

 to mark its position. The nearest approximation to its posi- 

 tion is from 100 to 150 feet below the lower Conglomerate, 

 or'fBirmingham Breccia." 



it is less prominent, but more persistent than either of the 

 preceding horizons. It may easily be traced for the greater 

 length of this valley. In some places it carries limonite ore, 

 in others red hematite. In some places both limonite and 

 hematite are found together, while in many others there is 

 no ore, and only a thick belt of irony rocks marks its posi- 

 tion. Usually in the upper part of this valley both the 

 limonite and hematite deposits and beds are thin, and may 

 not carry ore enough to be of economic value. But I am 

 informed by a note from Dr. E. A. Smith, State Geologist, 

 that in the lower part of the valley a bed four feet thick in 

 one place of red hematite ore has been found in the Lower 

 Silurian at Pratt's Ferry in Bibb county, and has been traced 

 to Birmingham. It belongs either to this horizon or the 

 next above it, the base of the Trenton. No others carry 

 red hematite ores, so far as yet observed. 



The Fourth Limonite Horizon is in this valley unimpor- 

 tant, as it carries but little ore. It is the base of the Trenton 

 formation, or rather the magnesian limestone, which often 



