treology of Tndianaj Sfc. 131 



Art. IV. Sketch of the Geology and Mineralogy of a 

 part of the State of Indiana, communicated in a Utter to 

 the Editor, by Mr. W. B. Stilsoj*. 



Louisville, (Ken.) August 11, 1818. 

 Dear Sir, 



X. HAVE employed a short period of leisure in passing oyer 

 a portion of the state of Indiana. Among other objects, I was 

 not wholly inattentive to the mineralogical and geological fea- 

 tures of the country, I now, with diffidence, transmit to you 

 the result of my inquiries. 



Sketch, &c. 



The secondary formation of the state of Indiana is abundantly 

 evident. The surface of the soil is undulating, and marked 

 with few elevations which deserve the name of mountains. 

 The rocks are sandstone, limestone, and clay-slate ; all of 

 which are disposed in horizontal strata. The sandstone pre- 

 sents nothing remarkable in its appearance. Its colours are 

 various shades of gray and brown. The principal hills are of 

 this formation. The principal colours of Ihe limestone are 

 blue and gray, and their various mingled and intermediate 

 shades. Its secondary formation is very manifest from its 

 almost earthy appearance. In innumerable instances, the 

 limestone rocks contain immense quantities of imbedded shells, 

 of great similarity in form and appearance, and having consi- 

 derable resemblance, to the common escallop-shell of the 

 ocean. Owing to the easy decomposition of these rocks, and 

 the horizontal position of their strata, they afford many sub- 

 terranean passages for water. A considerable stream, called 

 Lost River, runs into a cave in the side of a precipitous hill ; 

 and, after a passage of 6 or 7 miles under the earth, again 

 makes its appearance, with a large accession to its waters. 

 The traveller's attention is continually excited by cavities in 

 the earth, where the temporary rivulets, proceeding from 



