Association of American Geologists a7id Naturalists. 177 



Dr. Dana presented a copy of what was probably the first 

 work on the geology of America, entitled "Beytrage zur miner- 

 alogepfer Eeintre und des Cestlicheu theils von Nord America 

 und sum Gebiirsge von D. Johamre David Schopf," presented to 

 the library of the Boston Society of Natural History. Mr. Tes- 

 chemacher was requested to report on it. 



-'' Mr. Couthouy read a paper " on various icebergs as observed 

 by him."*^ 



Mr. James Hall read a paper " on wave lines and other mark- 

 ings on the surface of rocky strata in New York and other places." 

 Association adjourned to 3 J o'clock, P. M. 



Friday, 3^ o'clock, P. M.—Prof. Silliman in the chair. The 

 following gentlemen were announced by the standing committee 

 as the local committee for next year. Dr. T. Romeyn Beck, Prof. 

 E. Emmo7is, Albany, and Mr. W. C. Redfield, New York. 



A letter from Mr. James T. Hodge, relative to the distribu- 

 tion of State Reports, was read by the secretary. 



A paper was read -''on the Structure of the Appalachian chain, 

 as exemplifying the laws which have regulated the elevation of 

 great mountain chains generally ;" by Prof. Hem^y D. Rogers, 

 and Prof. William B. Rogers. 



The authors divide their papers into two parts : Part I, being a 

 description of the phenomena ; Part II, a theory of the flexure 

 and elevation, of the strata deduced from the preceding features 

 of structure. 



Part. I, embraces the following heads : 



1st. A sketch of the physical features of the Appalachian chain, 

 from New England to Alabama. 



2nd. Predominance of southeastern dips, with an historical sketch 

 of the previous explanations offered by other geologists. 



3rd. Of the character of the flexures of the strata, and the law of 

 their gradation in crossing the chain northwestward. Two or three 

 new terms are here proposed for designating conditions of structure. 

 The several prevailing forms of structure are then exemplified : (a,) 

 normal flexures ; (Z>,) folded flexures and inversions ; (c,) flexures bro- 

 ken on passing into faults. 



4th. Of the distribution of the axes in groups ; remarkable parallel- 

 ism of the axes in each group ; great length of some axes ; bending of 



* Mr. Couthouy's remarks have been already given, p. 154-165. 

 Vol. xLiu, No. 1.— April-June, 1842. 23 



