CARBONIFEROUS LIMESTONE. IO9 



cutting of it into vases, etc., and polishing it. The rest of the quar- 

 ries are worked in the ordinary style of stone quarries. In the 

 Grandville quarries, of the Grand Rapids Plaster Co., we find high- 

 est a series of argillaceous, drab-colored, easy weathering limestones 

 with seams of shale, which, locally, are found to be quite fossil- 

 iferous, containing several forms of Lamellibranch shells, Schizo- 

 dus, thick-shelled, large Nuculas, and other forms ; Brachiopods, such 

 as Chonetes, and an Orthoceratite, Crinoid stems, Bryozoa, etc., are 

 also found ; but in particular. Fish remains in somewhat worn condi- 

 tion are abundant. Scales, teeth, dorsal spines, and numerous copro- 

 lites, mixed with water-worn pieces of shale, sandstone, and quartz 

 pebbles, and cemented by carbonate of lime, compose the fossilif- 

 erous seams. The non-fossiliferous portions of this rock, which, on 

 chemical analysis, gave. 



Carbonate of lime 48 



- " magnesia 27 



Hydrate of iron oxide and alumina 4 



Argillaceous residue 18 



97 



might perhaps be converted into hydraulic cement. Below these 

 upper strata a white gypsum bed, a few feet in thickness, follows, 

 which in some places lies directly under the drift, and is very much 

 eroded and cut up into isolated blocks, quite surrounded by 

 drift material. The next lower strata, amounting to about 4 

 feet, are argillaceous limestones and soft, dark gray shales, which 

 rest on a heavy bed of gypsum from 8 to 12 feet in thickness. The 

 lowest strata seen in the quarry are again limestones and dark shales 

 with thin seams of white gypsum. In the lately opened Wyoming 

 Plaster quarries, about half a mile northwest of the Grandville Plaster 

 quarry, 25 feet of rock beds are uncovered. First come about 8 

 feet of drift, then 3 feet of a calcareous laminated sand rock with 

 purer limestone seams of a greenish-gray color ; next lower is a 5- 

 foot bed of white gypsum, then calcareous sand rock and dark 

 bluish shales, amounting to 7 or 8 feet ; lowest is a plaster bed, al- 

 ready penetrated to a depth of 17 feet without having reached its 

 limit. The lime and sand-rock beds are very plainly ripple-mark- 

 ed, and on some of the slabs are the relief casts of large, irregu- 



