Prof. Beck on Igneous Action, as exhibited in New York. 333 



Art. XVI. — Views concerning Igneous Action, chiefly as deduced 

 from the Phenomena presented by some of the Minerals and 

 Rocks of the State of Neio York ; by Lewis C. Beck, M. D., 

 Professor of Chemistry in Rutgers College, New Jersey.* 



[Read before the Association of American Geologists and Naturalists, April, 1843.] 



At the last meeting of the Association, I had the honor to sub- 

 mit some observations on the pseudomorphous minerals of New 

 York, and in attempting to refer the changes there described to a 

 general cause, I fixed upon igneous action as the one which was 

 most consistent with all the phenomena. 



The study of these and similar changes thus produced, and the 

 examination of certain minerals which are confessedly of igneous 

 origin, have led to some general views, which I now propose to 

 lay before this meeting, with the facts from which they have been 

 deduced. 



Of the rocks usually termed metamorphic, or those which are 

 supposed to have been changed by heat, there are numerous lo- 

 calities in the state of New York. Among these are white lime- 

 stone, dolomite, gneiss, and perhaps mica slate. In regard to the 

 white limestones, especially of St. Lawrence County, Dr. Emmons 

 has so clearly established their igneous origin, that I shall offer 

 nothing upon the general subject which he has elucidated. I 

 must, however, advert to the appearances which both here and 

 elsewhere some of the imbedded minerals exhibit. 



At the noted locality in the town of Hammond, St. Lawrence 

 County, the crystals of apatite, feldspar and pyroxene are often 

 variously bent, and have their angles smooth and rounded as if 

 by fusion, while crystals of zircon have been broken and their 

 terminations moved from their original position. In the same 

 county also, quartz crystals frequently occur with their termina- 

 tions rounded even in a more striking manner than in the prece- 

 ding minerals. 



A similar appearance is presented by the crystals of scapolite, 

 (Nuttallite,) which are found in great abundance in the white 

 limestone, in the town of Diana, Lewis County. Among hun- 

 dreds of specimens, there are very few which have their forms 



* Communicated to this Journal by the author. 



