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NEW YORK STATE MUSEUM 



in the dense brushwood. When dry, as it is during the summer 

 season, the stream bed may be recognized where it leaves the wood 

 and enters the flats, by the presence of much calcareous tufa. 

 The mine may also be approached by a steep path from above. 

 This begins as a wood road on the terrace about 100 feet below 

 the red barn of Mr George Acker on West hill. The path descends 

 over the cliffs about two thirds of a mile beyond Mr Acker's place. 

 The mine is in the form of a fissurelike tunnel [sec pi. 24] and 

 the mineral may be seen in the beds on both sides of the tunnel 

 in large geodic masses of a milk white color. Some of these have 

 the aspect of having replaced heads of Stromatopora or other 

 fossils. This mineral was formerly known as " marble," which it 

 resembles. Calcite, often in the form of nailhead spar, is found 

 in some of the geodes. 



The discovery of the strontianite was announced by Prof. Ebene- 

 zer Emmons in 1835. 1 It was at that time the only known deposit 

 of this mineral in the United States. 



The following description of the varieties is by Dr C. U. Shep- 

 ard of Yale University. 2 



The most obvious variety is that in acicular crystals, and mas- 

 sive in long, straight, divergent individuals. It occurs, occupying 

 irregular cavities, from half an inch to several inches across; the 

 crystals and fibrous masses being implanted upon a dark blue 

 calcareous spar which is granular in large individuals, or crystal- 

 lized in obscure scattered dodecahedra, whose apexes are replaced 

 by three, six, nine or 12 faces. The envelope of calcareous spar 

 is sometimes of considerable thickness, and is itself often included 

 within the layer of heavy spar, maisisive in large lamellar individ- 

 uals, some of which penetrate the calcareous spar. But the stron- 

 tianite constantly reposes upon the latter mineral. The crystals 

 are often % of an inch in length, and from the diameter of a 

 pin to that of a hair. The aggregated, columnar individuals fre- 

 quently exhibit at the extremity where they diverge most, crystal- 

 line faces. Some of these fibrous aggregations are two inches in 

 length, and bear a striking resemblance to certain varieties of 

 aragonite. Minute crystals of iron pyrites, crystallized in the 

 form of pentagonal dodecahedrons, are scatlered here and there 



'Am. Jour. Sri. 1S.T>. 27 :1S2. 



2 Am. Jour. Sri. 1835. 27:304-67. 



