SchoolcrafVs Localities. 47 



ted gypsum. This mass is about 9 inches in diameter, and 

 the limestone merely forms a crust around the aggregated 

 mass of crystals. 



Calcareous Spar. — Roche de Bout, on the Maumee ri- 

 ver, Wood County, Ohio. Imbedded in limestone, and 

 exhibiting its most common forms of crystalization. Fre- 

 quently in perfect dodecaedrons of a light yellow hue. Al- 

 so, massive and translucent, of a honey yellow colour, for- 

 ming the cement of a beautiful variety of puddingstone, on 

 the right bank of the Wabash, 5 leagues above the junction 

 of the Tippecanoe river, Indiana. 



Calcareous Tufa. — On the left bank of the Wabash, di- 

 rectly opposite the preceding. On reaching this part of 

 the river, the traveller who descends by water, after pas- 

 sing a sudden bend of the river, observes, on his right, a le- 

 vel prairie with a small Indian village upon its margin, and 

 upon his left, a long line of dark grey cliffs, with a precipi- 

 tous front upon the river, and covered with forest trees of a 

 small and recent growth. These cliiFs are a calcareous tufa, 

 more or less spons;y or vesicular in their structure, and im- 

 bed, plentifully, fragments of shells, stems of vegetables, 

 leaves, and other remains. The external surface is some- 

 what blackened, by the weather, but the fresh fracture dis- 

 closes a light grey, yellowish grey, or greyish white colour. 

 This is probably the newest rock formation between the 

 Ohio and the Mississippi rivers ! How extensive it is, can-^ 

 not be stated. It disappears, or is hid below alluvial soil, as 

 we approach the mouth of the Tippecanoe. 



Fibrous Gypsum. — Neekimenis,* or Goose Iisland, lake 

 Huron, Michigan Territory. This small island is situated 

 nine miles distant from Michilimackinac, on the route to 

 the Sault of St. Mary. The gypsum is imbedded in a kind 

 of loamy clay, which forms a pretty extensive flat, upon 

 the south-eastern end of the island, which has so little ele- 

 vation above the water, that it is partially inundated during 

 the prevalence of certain winds. The masses are detach- 

 ed. Sometimes the fibres are 4 or 5 inches long, and pos- 

 sess a pearly white colour. Where exposed to the air, they 

 are somewhat decayed, and broken down. This gypsum 

 is associated with a gray granular variety, imbedding small 



*'The name which the Aborigines apply to it. 



