46 MINERALOGY AND LITHOLOGY. 



deeper into the specimen, a needle can be followed in its curving course 

 through a distance two or three times the width of the field. 



The most interesting microscopic occurrence that I have observed is 

 in the actinolite schist of Pittsburg. The rock is a compound of actino- 

 lite and quartz, in which the quartz is penetrated by the delicate black 

 needles, to which I have already referred, while the actinolite contains 

 much larger and more perfect yellowish-red crystals of rutile, which show 

 very well the tetragonal, crystalline form of the species. The crystals 

 are apparently eight-sided ; and some of them possess the geniculations 

 so characteristic of the species. The crystals lie scattered about indefi- 

 nitely in the actinoHte ; and, as all the large crystals are in that mineral, 

 it may be assumed that the circumstances for the formation of crystals 

 of rutile were more favorable in that mineral, or at the time that it was 

 made, than in the case of the quartz. Fig. i on PI. 4 represents a much 

 magnified section of this rock, in which the condition of the rutile, both 

 in the actinolite and in the quartz, is shown. 



33. Pyrolusite [Ma Oj]. 



This ore of manganese is found at Winchester and Hinsdale, associ- 

 ated with the manganese silicate that occurs there. At Northwood, 

 tuberous and mammillary specimens have been found in the granite. It 

 is not an abundant mineral, but as a black incrustation, soiling the fin- 

 gers when touched, it is quite widely distributed. It is not found crys- 

 tallized in the state. 



34. LiMONiTE [Hg Fe4 O9]. 



Under this head, besides the pure mineral, the deposits of bog ore 

 will be noticed. In several places these bog ores have been extracted 

 for reduction ; and it is reported that excellent iron has been made from 

 them. In Lancaster, bog iron ore was found constituting the hardpan of 

 a meadow, and was easily extracted. In Bedford, Amherst, and Merri- 

 mack are deposits that have been worked. In Bath, a swamp deposit 

 was found beneath three feet of mud, and was easily broken up and 

 drawn out. In Madison, Dr. Jackson discovered a deposit in the bottom 

 of Six-mile pond. It is found in the low lands of Grafton and Lebanon, 



