162 Geological Observations upon 



Art. XXI. — Geological Observations upon Alabama, Georgia and 

 Florida; by Charles U. Shepard, 



In ascending the Alabama River, during the month of January 

 last, occasional opportunities were presented me for observing the 

 geological features of the country bordering on that river ; although 

 they were limited to such stoppages as were made by the boat in 

 wooding, or in discharging freight. Since my return to the north, I 

 find I have been preceded, in part, in the nature of my researches;* 

 but, as I am able to indicate certain localities, and to particularize a 

 {q\v fossils, the notices I had anticipated may not appear wholly su- 

 perfluous. 



The result of my observations upon the formations of this district 

 lead me, for the present, to regard them as of earlier date than those 

 of the Ferruginous Sand Formation of New Jersey and Maryland, 

 and as belonging to the Plastic Clay of the Tertiary; a more ex- 

 tended series of observations, however, may establish the opinion 

 respecting them entertained by Dr. Morton. 



My first observations were made at Prairie BlufF, a place fifty 

 miles above Claiborne, upon the west side of the river. The river 

 passes directly under the side of the bluff, which is sixty or seventy 

 feet high and six or eight hundred feet long, exposing a perpendicu- 

 lar section of a white, slightly cohering sandstone, which is imper- 

 fectly stratified, and in many places fast crumbling down into sand. 

 The grains composing this rock are scarcely larger than a pin's head ; 

 and are white and transparent. The principal cement, or cause of 

 its integrity, appeared to be the shells it embraced, and an occasional 

 admixture of white clay. Amongst the ruins of this rock, I gather- 

 ed very distinct specimens of Exogyra costata, a large species of 

 Gryphea, (mutabilis?), Ostrea falcata, (intermediate between the com- 

 mon New Jersey variety and the variety nasuta, figured by Dr. Mor- 

 ton, the shell extremely thin and fragile,) a species of Cyrena, casts 

 of a Natica, a very thin shelled Terebratula? Turbinolia and Ver- 

 micularia. 



Five miles above, at Campbell's Landing, which is upon the same 

 side of the river, I visited another bluff of smaller extent, in which 



* Vid. this Journal, Vol. XXII, p. 94, and Vol. XXIII, p. 228. 



