Association of American Geologists. 177 



the coal region of Dauphin and Lebanon counties, east of the 

 Susquehanna. 



Thursday, 4 o'clock, P. M. — The Association assembled at 

 the rooms of Mr. Taylor, where that gentleman exhibited a highly 

 interesting model in plaster of the Dauphin and Lebanon coal re- 

 gion, embracing, altogether, an area of seven hundred and twenty 

 square miles, showing the range of the mountain elevations, with 

 their relative height and position ; also their elevation above tide 

 level ; the dip of the rocks, the position of the coal seams, and 

 much other useful information. 



Mr. Taylor accompanied this exhibition with remarks explan- 

 atory and statistical, in relation to this coal region, and made 

 some observations on the importance of this mode of exhibiting 

 the geological features of a country, expressing the hope that the 

 day would come when models of this kind, representing the sev- 

 eral states, and even the whole United States, shall be constructed. 

 He also enlarged upon the propriety of following, as closely as 

 possible, the actual conformation of the country in drawing sec- 

 tions, and of adopting uniform modes of illustration by colors, 

 &.C., and the importance of an equal scale of extension and ele- 

 vation as far as practicable in such sections.* 



Prof. H. D. Rogers followed with observations upon the 

 Pennsylvania coal formations and the range of their underlying 

 rocks, detailing what he conceived to be the cause of the inverted 

 dip observable along the southern border of the Kittatiny series, 

 ascribing it to a great force acting laterally, and folding and crush- 

 ing the axes so as to produce this inverted dip by tossing the 

 strata many degrees beyond the perpendicular, and thus produ- 

 cing the present apparent dip of the lower stratified or sedimentary 

 rocks beneath the primary. 



Adjourned to half past nine o'clock to-morrow morning. 



In the evening, the members of the Association had the pleasure, 

 in common with a number of citizens, of listening to a very inter- 

 esting and appropriate address from Prof Hitchcock, embracing all 

 the points at present most interesting to the American geologist.f 



* See Mr. Taylor's article published entire, with a colored section, in the pres- 

 ent number of this Journal. — B. S. Jr. 



f As this address is to be published entire by the Association, and it is intended 

 to give an abstract of it in the next number of this Journal, no farther notice of it 

 is inserted here. — B. S. Jr. 



Vol. xLi, No. 1.— April-June, 1841. 23 



