Mineral Contents. 



179 



upper part of the mine ; and he considers this the roof of " the vast 

 bed of clay, which forms the immediate enveloping matter of the ore." 

 Although I have not visited the ore beds in Kent, t must be permit- 

 ted to doubt whether there be not a deception in respect to this point. 

 For the occurrence of a " vast bed of clay," unconsolidated, in gneiss 

 or mica slate, is such a perfect anomaly in geology, that it cannot be 

 admitted without the strongest evidence. And when I find these ore 

 beds at Salisbury, West Stockbridge, Richmond, and Lenox, most 

 obviously lying above the primary rocks, I cannot but suspect that this 

 is the case also at Kent: though I would not close my eyes against 

 evidence to the contrary. 



If it be admitted that this hydrate of iron belongs to a tertiary for- 

 mation, it by no means follows that its deposition was isochronous 

 with that of the newest tertiary in the valley of the Connecticut : and 

 the occurrence in the former, of so much iron, while it is very spar- 

 ingly diseminated in the latter, is a presumptive argument against 

 their production in the same menstruum. 



The principal beds of the hydrate of iron in Berkshire county, are 

 found in West Stockbridge, Richmond, and Lenox. Out of Massa- 

 chusetts, the beds at Bennington, Vt. and at Salisbury and Kent, Ct 

 are best known. The most common varieties are the brown hema- 

 tite, and compact brown oxide, though the ochrey brown oxide is 

 very common, as well as the argillaceous oxide. The hematite is 

 often beautifully mamillary and stalactical. (Nos. 53, 54, 55.) 



No one looks at the stalactical specimens of this ore, without en- 

 quiring at once, whether heat must not have been concerned in its 

 production. For the specimens exceedingly resemble certain stalac- 

 tical varieties of lava, or the products of a powerful iron furnace. 

 And in their natural position, the stalactites usually hang in a per- 

 pendicular position, as they would do if formed by the dripping of 

 tenacious melted matter. But after all, there seem to be insuperable 

 difficulties in admitting the igneous origin of hematite. For how- 

 could heat have operated powerfully enough upon the hematite to 

 melt it, without melting, or at jeast indurating, the clay in which it is 

 enveloped ? Again, the occurrence of this ore in calcareous spar 

 and quartz, (which are usually of aqueous origin,) shows that it 

 may be produced from water. It is likewise now admitted, I believe, 

 by the ablest mineralogists,* that argillaceous oxide of iron and bog 



* Beudant's Minerologie, Vol. 2. p. 702 : Dictionaire Classique D' Historie Natu- 

 relle, Art. Fer Hydrate or Hydroxide : also Mohs Mineralogy, Vol. 2. p. 410, 



