852 APPENDIX. 



white color in inferior situations, but the surface is somewhat 

 colored by fallen leaves and other decaying vegetation. It imbeds 

 fluvatile shells and some vegetable remains, the species of which 

 have not been ascertained. The opposite, or west side of the 

 river consists of a kind of puddingstone, or caschalo, made up of 

 pebbles of quartz, &c., cemented by carbonate of lime, of a yellow 

 color and translucent. This beautiful aggregate is overlayed by 

 a stratum, of fifteen or twenty feet in thickness, of diluvial soil. 

 These localities fall within the limits of the State of Indiana; but 

 on territories still occupied, if not owned, by the aborigines. 



3. Pseiidomorphons Garhoyiate of Lime. — This form of carbonate 

 of lime occurs in Pope County, Illinois, a district celebrated for 

 its fluorspar, lead, crystallized quartz, (fee, and bearing the un- 

 equivocal marks of a secondary formation. Scattered in large 

 masses over the soil, we observe compact limestone, with very 

 perfect cubical, octahedral, or other regular cavities, which have 

 manifestly originated from crystals of fluorspar. The most com- 

 mon impress of this kind appears to have resulted from two cubes 

 variously joined — a form of appearance very common to the Illi- 

 nois fluates. Some of these cubical cavities exceed three inches 

 square; but in no case is any remaining portion of the spar in 

 these cavities, or anywise connected with the fragments of lime- 

 stone thus impressed, although, at the same time, the spar is very 

 abundant in the alluvial soil where these curious limestones are 

 found. 



2. Sulphate of Lime. 

 Subs. Gi/psum. 



1. Fibrous Gypsum. — In the alluvial soil of the St. Martin's 

 Islands, Lake Huron. The fibres are sometimes five or six inches 

 in length, of a white color and delicate crystalline lustre. Some- 

 times these fibrous masses are partially colored yellow or brown, 

 apparently from the clay, or mixed alluvion, in which they are 

 imbedded. 



2. Granular Gypsum. ^ 



3. Granularly- Foliated Gijpsum. >"VYith the preceding. 



4. Earthy Gypsum. ) 



