Intelligence and Miscellaneous Articles. 363 



saturated with carbonic anhydride underwent chemical change, and 

 was converted into hydromuscovite by loss of magnesia and iron, 

 which were dissolved in the water. 



Lepidomelane in pure water became hydrated, but in carbonated 

 water also sustained a loss of iron. 



The author has ascertained that when anhydrous micas become 

 hydrated, or lower hydrated ones more highly hydrated, they increase 

 in bulk. 



XLIV. Intelligence and Miscellaneous Articles. 



ON THE OPHIOLITE OF THUEMAN, WAKRBN CO., N.Y., WITH 

 REMARKS ON THE EOZOON CANADENSE. BY GEORGE P. 

 MERRILL. 



THE Warren County Ophiolite, or Verdantique Marble, as seen 

 in the limited amount put upon the market, consists in its typical 

 development of an even granular admixture of white calcite and 

 pale yellowish-green serpentine in about equal proportions. The 

 uniformity of texture is, however, often interrupted by large irre- 

 gular blotches of deep lustrous-green serpentine, which, as shown 

 in a large block in the National Museum collection, sometimes 

 carry a white nucleus. The presence of this nucleal material, 

 which may frequently be observed passing by imperceptible grada- 

 tions into the green serpentinous material, suggested at once that 

 here, too, the serpentine is a metasomatic product, as the writer 

 has shown* is the case with that of Montville, New Jersey. Thin 

 sections of the rock under the microscope confirm this suggestion. 

 The white nucleal mineral is seen to be an aggregate of small 

 monoclinic pyroxenes, quite colourless in the thin sections, without 

 pleochroism, but polarizing brilliantly and giving extinctions on 

 cHnopinacoidal sections as high as 41°. Irregular canals of ser- 

 pentinous matter cut through these aggregates following cleavage- 

 and fracture-lines, and all stages of alteration, can, as in the Mont- 

 ville stone, often be observed in a single section. In the more 

 even-textured portions of the rocks the serpentine appears as 

 rounded or oval granules, with small enclosures of secondary cal- 

 cite imbedded in the large original plates of the same material. 

 Here, too, all stages of alteration are readily detected, some of the 

 pyroxene granules being traversed by but a few wavy threads of 

 the serpentinous matter, while in others not a trace of the original 

 mineral remains. Were it not for these fresh remaining por- 

 tions one would hesitate to pronounce them pyroxenic derivatives, 

 since they in no case show crystal outlines, but are mere oval 



* Proc. U.S. Nat. Mus. vol. xi. (1888) p. 105. 



