PETROGRAPHICAL PROVINCE OF ESSEX COUNTY 1 13 



glass present. Along the borders of the phenocrysts, both 

 quartz and feldspar, the hornblende needles are smaller and 

 crowded together, as if pushed aside by the growth of the large 

 crystal, in a manner quite analogous to that described by Pirsson T 

 in the case of a tinguaite from the Bearpaw Mountains. There 

 is no evidence of flow structure in the proper sense of the term. 



The hornblende is apparently a glaucophane-riebeckite, iden- 

 tical with that described elsewhere 2 in a solvsbergite from Cape 

 Ann. The extinction angle is small, pleochroism intense ; parallel 

 to the axes c and b dark blue-gray ; parallel to axis a pale yellow. 

 The position of the axes of elasticity could not be definitely 

 determined, but apparently C lies nearest to c, indicating that it 

 is a glaucophane. 



An analysis of this rock is given below, together with one of 

 the Texas paisanite and one of a grorudite from Norway. . The 

 paisanites were discovered by Osann as dikes in Transpecos, 

 Tex., and named after the Paisano Pass, where the types were 

 found. They are composed of quartz, alkali-feldspar, and rie- 

 beckite, in the Texas rocks this last forming blue spots in a white 

 groundmass, and quartz and feldspar being also phenocrystic. 



100.57 100.37 99-38 



I. Paisanite, Dike 3, Magnolia. H. S. Washington anal. 



II. Paisanite, Mosquez Canyon, Transpecos, Texas. A. Osann. Tsch. Min. Pet. 

 Mitth. XV, p. 439. 1895. 



III. Grorudite, Varingskollen, Norway. Sarnstrom anal. Brogger, op. cit., I, p. 

 48, 1894. 



1 Pirsson, Am. Jour. Sci. (4), II, p. 191, 1896. 



2 H. S. Washington, Am. Jour. Sci. (4), VI, p. 177, 1898. 



