DISTRIBUTION OF SPECIES. 31 



General nection at tialt Mountain, Alabama. 



Feet. 

 Limestone, with reef corals, contains tlie two species above mentioned, and other 



undetermined species, about 75 



Hard limestone with triturated shell remains, echinoid spines, etc 20 



Section of hill north side of Salt Creel- and cast side of small draw running into Salt 



Greek. 



Feet 



Bed of Ostrea vicksburgensis, many Bryozoa, etc., matrix marly 10 



Soft limestone, composed in large part of Orbitoides nmnielli, contains specimens 

 of Scutella, etc 30 



The top of this section is l)elow the Ijottom of the 2)receding' section. 



Smith^ gives the thickness of the Coral limestone as 150 feet. During 

 my visit to Salt Mountain I found his account of the sequence of the beds 

 absolutely correct, but several aneroid barometer measurements showed his 

 estimate of the thickness of the limestone actually composed of corals too 

 great. One of my measurements made it 90 feet and another 60 feet. I 

 believe bis estimate of the thickness of the beds above the Orbitoides nian- 

 telU zone correct. The corals here seem to have ffrown on a rising sea 

 bottom. 



Pumpelly^ and DalP have shown that in Florida the Upper Oligocene 

 rests unconformably on the Vicksburgian Lower Oligocene. We do not 

 know the relations of the Upper Oligocene to the Coral limestone in Ala- 

 bama, but quite probably the elevation that made the coral reef possible 

 carried it above the surface of the water, and it had the same relation to a 

 rising land as the West Indian elevated reefs described by Agassiz and Hill. 



Localities in Georgia. — Our collectious coutaiu specimeus from two localities 

 in Georgia. They are Russell Springs, Flint River, and Jacksonboro. The 

 species from the former locality are Stylophora minutissima Vaughan and 

 Astroca'uia pumpcUyi Vaughan, and from the latter Cladocora rescrescens 

 Lonsdale and Porites ramosa (Lonsdale). 



It is quite probable that both of these localities are in beds of high 

 Eocene or Lower Oligocene age. Russell Springs belongs to the Ocala 

 horizon of the Vicksburg. The corals from them indicate shallow water, a 

 depth not too great for the growth of reef corals. 



'Report on geology of Coastal Plain of Alabama: Geol. Survey Alabama, 1894, pp. 107, 108. 

 "Am. Jour. Sci., 3(1 ser., Vol. XL\'I, 1893, pp. 445 et seq. 

 ■'Bull. Oeol. Soc. Amer., Vol. V, 1894, p. 162. 



