300 T. H. Alclrich — Tertiary of Alabama. 



A.KT. XL. — Observations upon the Tertiary of Alabama; by 

 T. H. Aldrich. 



In the following article, the results of a personal examina- 

 tion of the Tertiary of Alabama are given so far as is necessary 

 to reply to the papers of Dr. Otto Meyer in the June and July 

 numbers of this Journal, entitled " The Genealogy and the Age 

 of the species in the Southern Old-tertiary." 



The proof of the stratigraphical relationship, as worked out 

 by Dr. Meyer, rests upon quotations from previous writers upon 

 the subject, and upon a theory of descent and resemblance, 

 which Dr. Meyer applies to the fossils of the different groups. 

 There does not seem to be any positive statement in his articles 

 that the superposition of the beds as given by him came under 

 his actual observation, therefore I shall proceed by giving the 

 stratigraphy at different points, and then some remarks upon 

 his identifications of species. 



The old town of Claiborne, Ala., is built upon what is 

 locally known as " second bottom " of the Alabama Eiver, a 

 level sandy plain over a mile wide at this place ; Jackson on 

 the Tombigbee River, and Selma and part of Montgomery,, 

 both upon the Alabama River, are built upon the same terrace 

 and present almost precisely the same topographical features 

 as Claiborne. 



This terrace apparently is the oldest upon these rivers and 

 has been subject to extensive erosion. The drift following 

 filled up the depressions to a level plain, on the remains of 

 which Claiborne now stands. 



Going toward Perdue Hill through the main street of Clai- 

 borne (which runs in a southeasterly direction) at a point about 

 one and a half miles back we reach the base of the hill ; as we 

 ascend it we find, in the road and gullies alongside, limy spots 

 indicating the presence of the " White Limestone " below, and 

 at a point about two miles from the bluff, on the side of the 

 road, there is an outcropping of the White Limestone highly 

 charged with Orbitoides and casts of several different forms 

 of shells ; by the aneroid barometer this point is 110 feet 

 above the top of the bluff at the river. These limy spots con- 

 tinue to show still higher, with an occasional outcrop nearly to 

 the top of the hill. The crown of the hill is covered with the 

 red loam, and is 180 feet above the top of the bluff. 



The dip of the strata at Claiborne seems to be a little west 

 of south, therefore this street is very nearly upon the strike. 

 This fact, together with the difference in level, plainly proves 

 that at Claiborne itself the White Limestone is above the 

 Claiborne group. The dip of the strata can be shown by 



