I06 NEW YORK STATE MUSEUM 



taken, is here called the Barton hill. It is possible i.iai this bed 

 swings around to the east under the drift and is the basis of the two 

 Harmony shafts, south of the Mineville groups \se€ map: fig. 19]. 

 Yet there is still much uncertainty about this connection. 



At the north end of the Barton Hill group a gap of concealed and 

 drift-covered fields intervenes with no demonstrated ores. After 

 half a mile, ore again appears in two bands one over the other, at 

 the openings called the Fisher hill and Burt lot, both on the 1600-40 

 foot contours and now for 10 years or so idle. 



A half mile east of Fisher hill and on the 1450 contour of another 

 hill, is the recently revived Smith mine, whose ore body is tapped 

 still lower doA\Ti by the O'Neill shaft. Another internal ensues to 

 the north and then after half a mile two old-time but long aban- 

 doned mines are met, called the Hall and the Sherman. The former 

 is one of the oldest in this locality and is mentioned by Professor 

 Emmons. Drilling has recently been in progress in exploring them, 

 but no mining has been done for many years. Still farther north 

 no ores are known for several miles. 



Mineville group. These great ore bodies are the chief source of 

 the local production, and they present a mass of noble proportions. 

 Thanks to the liberal spirit and courtesy of the two companies, and 

 to the excellent and careful records of the engineers they can be so 

 well illustrated that with the solitary exception of the Tilly Foster 

 mine in Putnam count}', they give us the best idea of the general 

 shape and relations of a magnetite body yet afforded in this 

 cotmtr}'. At the latter the structural relations are simpler, and the 

 amotmt of ore much less. The Mineville group presents a very 

 violent case of folding, accompanied by stretching and pinching 

 oi the crest. The ores are in a pitching fold which makes depth 

 rapidly to the southwest, so that we have to keep the relations 

 constantly in mind in terms of solid or three-dimensional geometry-. 

 At the north end we have further to deal with a series of faults 

 and a ver\- puzzling relationship, which on the basis oi one bed 

 of ore is not easy to satisfactorily clear up. In the present descrip- 

 tion, the writer's paper and sections prepared in 1897 and pub- 

 lished in the Transactions of the American Institute of Mining 

 Engineers, volume '2'j, pages 146-204, are brought up to date and 

 are made to include the results of 10 years of mining. 



There are three principal and separate faulted parts of one great 

 bed, viz: roughly from north to south, the ^liiler, the Old Bed or 

 Mine 2^ 1 the first discovered under the name of the Sanford 

 pit) and the '" 21 "-Bonanza-Joker continuous ore body, the chief 



