240 Prof. Silliman's. Address before the 



— fifty or sixty feet — has been discovered, in situ, near Abingdon 

 in Virginia, along with gypsum shale, and probably sandstone. 

 There are abundant salt fountains at the same place, and the 

 mineral salt was discovered in boring for salt water. 



This is an interesting feature, added to our geology. We had 

 before vast numbers of salt springs, but no sohd mineral salt short 

 of the Rocky Mountains, There, in a mountain on the Sal- 

 mon River, it was observed some years ago, by the Rev. Mr. 

 Parker, a missionary, who reports it to be floored and roofed by 

 sandstone. (This Jour. Vol. xli, p. 214.) 



The tin ore, (oxide of tin,) reported last year, as discovered 

 by Dr. Jackson in the White Mountains, has been found by him 

 in increasing quantity, and small bars or ingots of the metal have 

 been extracted by the discoverer. This is an important addition 

 to our metallic resources ; and the extraction of metallic zinc 

 from blende (the sulphuret) by Dr. Jackson, from the ore found 

 at Eaton, New Hampshire, agreeably to the practice now adopted 

 in Germany, is a happy beginning upon an ore heretofore re- 

 garded as of little value, but existing in great quantities in the 

 United States. 



We forbear to dilate upon the simplicity and immensity of 

 many of our geological formations — a vast country constructed 

 upon one great model, with such unity of design and with such 

 persistence in the plan, that particular formations are found as- 

 sociated and running longitudinally northerly and southerly, 

 through the entire continent. 



The best architectural materials, granites, traps, porphyries, 

 sienites, serpentines, soapstones, limestones, primary slates, and 

 slaty rocks of every geological age, sandstones and conglomerates, 

 abound. The most useful minerals are found also in large quan- 

 tity — ores of iron, copper and lead, gold and silver, the latter 

 especially as it exists in argentiferous galenas. Above all, coal- 

 fields of unequalled magnitude, thickness, extent, and richness, 

 with clays, marls, and sands, and soils, of every variety, furnish 

 to our population all the means of national wealth and individual 

 prosperity. Over vast regions, there has been no serious distur- 

 bance of the strata ; they have been gently lifted from the waves, 

 often without a fracture, dislocation, or an intrusion of an igneous 

 rock, for hundreds of miles. This geological quietude affords 

 vast advantage in working our coal-fields, especially the trans- 



