1 8 Bulletin 9 310 



^8-6^, '88, — Hilgard. Conh'ib. Gcol. and Paleont. 

 U. S.,p.j2, '^/, — Heilprin. 



Contrary to the prevailing ideas heretofore expressed, we 

 believe the trul}' Lignitic deposits, i. e. those representing the 

 Tyignitic as we define them in Alabama, are not extensively 

 developed in Mississippi save perhaps in the northern counties 

 where the}- presumably represent the southern extension of 

 Safford's La Grange group, and perhaps Bluff sand. Bordering 

 the Cretaceous on the east are the Flat woods clays represent- 

 ing doutless the Midway. On the west or southwest there is a 

 fossiliferous Lower Claiborne horizon as indicated to some ex- 

 tent on Hilgard's map accompanying his report on the Agricul- 

 ture and Geology of Mississippi. The ' ' outlier ' ' of this 

 latter horizon about Vaiden is doubtless simply a fossiliferous 

 phase of the same and should be connecfted with the Lower 

 Claiborne to the southeast, thus embracing a considerable of 

 the so-called ' ' Northern Lignitic ' ' area in the Lower Claiborne. 

 So far as we are aware no molluscan fossils have been found 

 in the Lignitic of this State ; that the fossils at Vaiden are of 

 Lower Claiborne age there can be no doubt for we have made 

 satisfadlory colle<ftions from that locality. 



Hilgard in 1871 subdivided his Lignitic into Flatwoods and 

 La Grange beds, and gave them the total thickness of 450 feet. 

 From our observations in Tennessee, Mississippi and Alabama 

 it would seem that 200 feet would not be an unreasonable 

 estimate for the Midway ( Flatwoods ) beds of this State, 

 leaving therefore 290 of La Grange deposits. 



Heilprin has suggested an extension overlapping in this ' 'North- 

 ern Lignitic" of Jackson beds, including the Vaiden fossilif- 

 erous deposits. In this he is wrong, for the Jackson beds as 

 they passed northward would pass west of Vaiden, through 

 the Yazoo- Mississippi flats where they have long since been 

 carried away. The Arkansas limb of the northern extension 

 of the Jackson is in a better state of preservation. 



Alabama. 



References : — Trans. Amer. Philos. Soc., vol. 6, ist ser. p. ^11, 

 180 p, — Maclure. Trans. Amer. Philos. Soc, vol. 

 i, 2d ser., i8iy, — Maclure. Jour. Acad. Nat. 



