6 Bulletin of the New York State Museum. 



a parallel growth. Color is also a varying characteristic of these 

 tourmalines. In northern New Jersey, for instance, the crystals 

 have a faded, appearance, evidently not arising from incipient de- 

 composition, since, on all sides they present a highly vitreous 

 lustre, and the polish of the surfaces is hardly broken. So far 

 as instances have come under my personal observation this rule 

 admits of hardly an exception. In the New York limestones, how- 

 ever, even when the color is not deep there is a vividness about 

 them which makes a decided contrast to the New Jersey crystals. I 

 mentioned the fact that these crystals often had the appearance of 

 being nearly or quite dissolved. In addition it will be well to state 

 that this condition is owing to other causes than solution. Within 

 most of the crystals of larger size, rounded masses of calcite, as 

 coarsely crystallized as the surrounding rock, are enclosed and also 

 globules of quartz. 



The tourmaline is distributed irregularly through the entire mass 

 of the limestone in the localities named. Graphite, apatite, sphene 

 and wernerite are associated with it. Quartz, crystallized, is found very 

 rarely, but it is quite abundant, either as irregular shaped, pitted nod- 

 ules or as flattened and warped plates with the same pitted appearance. 

 The graphite occurs in thin laminae, often iu decidedly hexagonal 

 tablets. Though generally lying between the crystals of calcite and 

 parallel to their faces it often cuts through them irregularly and is 

 found enclosed in the body of nearly all of its associates. 



The limestone itself is very coarsely crystalline, some of the 

 cleavage surfaces measuring a cm., more or less. The color varies 

 from a dull grayish-white, to white, blue and red. Cleavage pieces 

 vary from dull opaque-milky to almost transparent. 



The foregoing, are briefly, the general characteristics of the 

 Laurentiau limestones in localities which I have visited. In the im- 

 mediate vicinity of Newcomb these characteristics remain the same. 

 Everywhere are evidences of intense metamorphism. 



One very limited area, however, presents an entirely different 

 appearance. The area covered by the " brown tourmaline locality,"* 

 is about ten feet wide by fifteen broad, and from three to five feet in 

 depth. In this pocket the limestone has been changed to an almost 

 transparent, yellowish- white and coarsely crystallized calcite. Embed- 

 ded in this gangue the following minerals were found in good crystals, 

 some very line : Tourmaline, brown and green, blue apatite, sphene, 



