GO TRANSACTIONS OF THE [fEB. 1, 



The Elaeolite Syenite near Beemerville, Sussex Co., N. J. 



BY J. F. KEMP, COLUMBIA COLLEGE. 



The elaeolite syenite exposure near Beemerville, N. J., is of great 

 interest, not alone because it is a rare and unique type of rock, but 

 also because it is quite remote from any other igneous outbreak 

 which is commensurate with it. Throughout the whole adjacent 

 region only .sedimentary and metamorphic rocks occur, with the ex- 

 ception of a few subordinate Ijasic dikes. 



Elaeolite syenites are not abundant the world over, and are only 

 known in a few places on tliis continent. The other American- ex- 

 posures are at Montreal, Canada ; Litchfield, Maine ; Salem and 

 Marblehead, Massachusetts; and the region about Magnet Cove, 

 Arkansas. The hornblende syenites described by Hawes from New 

 Hampshire have also been lately shown to contain elaeolite by W. 

 S. Bayley. (Geol. Soc. of America, Columbus meeting, 1891.) 



Basic dike rocks of a kind usually found in association with elae- 

 olite syenites have been recently .studied by the writer on Lake 

 Champlain, and it w^ould be quite natural if an exposure should be 

 found in the neighboring Adirondacks.^ 



Rocks with elaeolite or nepheline were announced years ago by 

 Hunt'' from Montreal, and Ro.senbusch speaks familiarly of the sy- 

 enite in his second edition, evidently from .specimens.^ Mr. Lacroix* 

 has also published a short preliminary note, and a subsequent fuller 

 account which appeared in 189L^ The syenites at Montreal were 

 intruded after the close of the Lower Silurian and before the Lower 

 Helderberg. The elaeolite syenite at Litchfield, Maine, has received 

 as yet but limited petrographic study, and the most that has been 

 written concerns its mineralogy. C. T. JacLson/ J. D. Whitney," 

 W. Gibbs,« and F. W. Clarke* have written of them. The last- 

 named considers the sodalite as derived from elaeolite. Elaeolite 

 syenite in boulders at Salem, Massachusetts, has been briefly noted 



1 .J. F. Kemp and V. F. Marsters, Trap Dikes of the Lake Champlain Val- 

 lev, etc. Annals, N. Y. Acad, of Sci., 1891. 

 '2 T. S. Hunt, Geol. Surv. Canada, 1883, p. 665. 

 3 Massige Gesteine, p. 90. 

 * A. Lacroix, Comptes Rendns, .June 2, 1890, p. 1152. 



5 Syenite-nephelinique de Montreal, Bull. Soc. Geol. de France, 1889-90, p. 

 323. 



6 C. T. .Jackson, Cancrinite, Nepheline, Zircon, from Litchfield, Me., Proc. 

 Geol. Soc, 1845, Am. Jour. Sci., ii, i, 119. 



■^ J. D. Whitney, Poggendorf's Annalen, Ixx, 431. 



^ W. Giblis, Poggendorf's Annalen, Ixxi, 559. "" 



9 F. W. Clarke.'The Minerals of Litchfield, Me., A. J. S., iii, xxxi, 262. W. 

 S. Bayley's paper, read at the Columbus meeting G. S. A., Christmas, 1891, 

 will appear too late for comparisoti in this cojitri button. 



