34 



17. Potsdam sandstone, with spherical concretions. Vicinity of 



the Caledonia or old Parish iron mine, Rossie, St. Lawrence 

 county. 



18. Serpentine and steatitic pyroxene. Village of Gouverneur, 



St. Lawrence county. 



19. Sphene (black) in crystals, imbedded in Gneiss. Near Gouver- 



neur village, St. Lawrence county. 



20. Calcareous spar. Banks of Vrooman's lake, Antwerp, Jefferson 



county. 



21. Iron sand, (magnetic.) Shore of Buonaparte's lake, Diana, Lewis 



county. 



22. Cast of the labrtjm of an Isoteltjs. Found in Ohio. 



23. DODECAHEDRAL CRYSTALS OF SULPHURET OF IRON. Farm of John 



Robinson, Gouverneur, St. Lawrence county. 



24. Cubic crystals of sulphuret of iron. Same locality. 



25. Spinelle, (pale red.) Farm of Mr. Ayers, Gouverneur, near 



Somerville, St. Lawrence county. 



26. Calcareous tufa. Martinsburgh, Lewis county. 



27. Crystalized mica. (5 specimens.) Vrooman's lake, Antwerp, Jef- 



ferson county. 



28. Minute capillary crystals of sulphuret of nickel. Found on 



Ankerite, and associated with Cacoxenite. Sterling iron 

 mine, Antwerp, Jefferson county. 



29. Potsdam sandstone, (cylindrical structure.) Rossie, St. Law- 



rence county. 



This curious structure is frequently observed in this section of the 

 country, and I do not recollect of having seen a satisfactory theory 

 to account for its formation. These cylindrical masses are of all sizes, 

 from three inches, to fifteen or twenty feet in diameter ; and their axes 

 are always nearly, if not exactly vertical. At times, two or more en- 

 croach on each other. 



The large circle represented in the following figure, is about twelve 

 feet in diameter, at the locality in Somerville, and the whole is nearly 

 of the same level. The concentric lines of stratification are sometimes 

 obscure, but the cylindrical structure is always sufficiently apparent. 

 To no active agent can we attribute these interesting appearances with 

 more plausibility, than that of water, revolving in the little vortices or 

 eddies, and causing the sand, which is the principal constituent in the 



