EARLY GEOLOOICAL SURVEYS 161 



mainder of the year Prof. M. W. Twitchell, of the State University, was 

 State Geologist, but after 1911 no provision was made for the continuance 

 of the Survey. 



The third decade of the nineteenth century was also an important one 

 in the history of southern geology. 



The first Geological Survey of Tennessee was authorized by the legis- 

 lature in 1831 and continued until 1850, under the direction of Gerard 

 Troost. During this time Doctor Troost made nine reports, two of which 

 do not appear to have been pubMshed. These reports, though short, con- 

 tain, according to Doctor Safford, much valuable material.® 



Work of T. A. Conrad, Isaac Lea, and Angelo Heilprin 



The year 1832 is conspicuous in the geological history of the Missis- 

 sippi Embayment by reason of the beginning of a publication by Timothy 

 A. Conrad, the "Fossil Shells of the Tertiary Formations of North 

 America," the second and third numbers of which were devoted chiefly to 

 descriptions of the Eocene shells of Claiborne, Alabama, with figures 

 drawn by Mr. Conrad. The third number, published in 1835, contained 

 a geological map of Alabama, which, so far as I know, is the first pub- 

 lished geological map of the state. In this map the following formations 

 are delineated: Primary, Carboniferous or Grauwacke, Bituminous Coal, 

 Greensand, Newer Cretaceous, Eocene, and Eecent. 



In November, 1833, appeared Isaac Lea's "Contributions to Geology," 

 devoted mainly to descriptions of Eocene shells from Claiborne, Alabama, 

 collected and sent to Doctor Lea by Mr. Charles Tait, of Claiborne. 

 Nearly all these shells were described about the same time by Conrad, as 

 above indicated, and an unfortunate controversy as to priority arose be- 

 tween the two men. The duplication of the names of the Claiborne shells 

 has naturally been a very great inconvenience to later students. 



The continuation of Conrad's work in 1838 was concerned with the 

 fossils of the Medial Tertiary, mainly along the Atlantic coast. From 

 1837 to 1842 Conrad was connected with the Geological Survey of New 

 York and contributed a number of reports on the Paleozoic fossils of that 

 state. 



His subsequent work may best be spoken of here, though out of chrono- 

 logical order. 



« Dr. Alfred H. Brooks, of Washington, has made the suggestion that the prominence 

 given to agriculture in many of the earlier Geological Survey Reports is due in part at 

 least to the fact that the states were fearful of losing much of their population by 

 migrations to the richer lands of the Mississippi Basin. 



XI — Bull. Geol. Soc. Am., Vol. 25, 1013 



