282 ON THE GEOLOGY AND 



The direction, inclination and dip of this lime- 

 stone are the same as those of the aforementioned 

 sienite. It has been traced upon a distance of about 

 eight miles, with few or no interruptions, to wit : 

 from Sparta at the south-west to one mile beyond 

 Franklin to the north-east, and even as far as Ham- 

 burgh, as we were informed ; although this limestone 

 is subordinate to the sienite, still masses of sienite 

 are found in it. We shall have occasion to refer to 

 these masses when we come to speak of the minerals 

 found in that vicinity. 



From the great abundance and importance of the 

 metallic deposits which occur in the sienite of Frank- 

 lin, we think it proper to connect the description of 

 their geological characters, with that of the formation 

 in which tbey exist. 



These metallic deposits consist chiefly in oxidule 

 of iron or common magnetic iron ore, Franklinite 

 and red zinc ore. The oxidule of iron is found in 

 large flattened masses, parallel to the divisions in 

 the sienite ; it occurs in the sienite only and is al- 

 ways inferior to the Franklinite ; it never comes in 

 contact with the limestone ; near it, the sienite is 

 often of a coarser grain, so as to present masses of 

 pure feldspar or hornblende near the ore. The 

 oxidule is sometimes considerably intermixed with 

 graphite; so much so as to prevent its being worked 

 for iron. The Franklinite and red zinc ore form 

 a mass which has I een traced upon upwards of five 

 miles, and whose breadth or thickness is rarely 

 less than ten, and is often thirty or more feet. Its 



