196 EXPEDITION TO THE 



appearance, or at least much less so than the inferior beds; 

 it contains specks and some veins of calcareous spar and 

 gypsum ; also crystals of quartz, &c. ; it likewise offers 

 sometimes specks of galena. It generally presents but few 

 petrifactions, Corallites and Millepores, as well as several 

 species of Terebratulites ; Ammonites, &.c. have been found 

 in it." 



"Above this compact limestone another stratum of calca- 

 reous rock is found which is known in the country under 

 the name of rauchwacke, (smoky wacke ;) it is a limestone 

 probably intermixed with silex, of a dark-gray, sometime? 

 blackish colour, with a somewhat scaly fracture, occasion- 

 ally fine-^'ained, sometimes though seldom oolitic, hard, 

 tough, and filled with pores or cavities ; this last feature 

 is characteristic ; it may be observed even in those parts 

 of the stratum which appear most compact ; the cavities are 

 angular, long, and narrow, (as in a cracked clay ;) the in- 

 terior of the cavities is lined with small crystals of calc- 

 spar, these cavities are sometimes large, being several 

 yards in length and breadth, &c." 



He afterwards proceeds to describe the ashes or pul- 

 verulent substance found near it. This, from its great simi- 

 larity to the residue of the combustion of wood, is desig- 

 nated in Germany by the name of asche, (ashes.) These 

 characters, when taken into connection, appear to us to 

 correspond so well with those observed on the Wasse- 

 mon, on the Mississippi, and throughout the country 

 between Rock river and Prairie du Chien, that we 

 feel strongly induced to consider the limestone of this 

 country as analogous to that observed bj^ Mr. Freiesleben. 

 This limestone is by some European continental geologists 

 referred to the Lias of English geologists ; but we would 



