VALLEY OF THE MISSISSIPPI. 27 



collected for lixiviation, and that the solid stone it- 

 self is also occasionally broken and submitted to the 

 same process. I am not acquainted with the existence 

 of many localities of nitre on the west side of the 

 Mississippi, though it has been obtained in considera- 

 ble quantity along the banks of the Meremek, and 

 some of the streams emptying into the lower part of 

 the Missouri. The Hirundel rocks on the banks of the 

 Arkansa possess the only appearance of affording 

 nitre which I have seen in that territory. 



I have termed the production of salt in this forma- 

 tion as anomalous v regarding any connection which it 

 bears with the ordinary gypseous or red-clay forma- 

 tion of the European geologists. No doubt numerous 

 pern arks have been made upon this subject, which I 

 now merely examine as a matter of fact. Every one 

 knows the abundance of salt springs which exist in 

 the valley of the Ohio and its tributary branches. 

 The most productive among them are the springs of 

 the Kenhaway and the Big Bone Lick. Those of 

 Onondago Lake, in the western part of the state of 

 New- York, are no less important. In my enquiries 

 and personal examinations, I must confess myself 

 to be generally at a loss to ascertain the proper ori- 

 gin of these springs. In no instance is this salt met 

 with in a solid form, nor in distinct connection with 

 gypsum, or with red coloured clays. The argilla- 

 ceous soils, indeed, which do occur, are dark gray 

 or grayish blue. At the Big Bone or Mammoth 

 Lick on the Ohio, and in many other places, where. 



