404 JULIEN 



enstatite/ and of olivine,^ at contact of lime-feldspar, have been 

 observed in gabbros of our Southern States and of Europe. 

 They have been commonly attributed to magmatic reaction 

 before consolidation of the rock — a hypothesis open to ques- 

 tion"^ — rather than to change during its subsequent meta- 

 morphism. 



In this connection reference may be made to a specimen of 

 aphanitic texture, obtained by VV, H. Hobbs {Bull. Geol. Soc. 

 Am., XVI, 1905, 169) from Man-o'-vvar reef in East River, 

 east of Manhattan Island, supposed to be " a dense basalt like 

 that so characteristic of the Newark areas of the Atlantic bor- 

 der. It seems likely that this latter rock may be from a por- 

 tion of a narrow dike within the series of crystallines." Such 

 an intrusion in this series would be unique, if established. 

 Through the courtesy of Prof. Hobbs I have been supplied 

 with a portion of this specimen, which has been found in thin 

 section to consist of black indurated shale from the basal con- 

 tact of the Palisades, an altered form commonly distributed in 

 boulders over Manhattan Island and the vicinage of Brooklyn. 



Occlusions of Westchester County, Nezv York. — To the north 

 and northeast of Manhattan Island and New York City, similar 

 intrusions are frequently found through Westchester County. 

 Outcrops of pegmatite, diorite or hornblende-schist, hornblende- 

 gneiss, biotitic gneiss and schist and ''serpentine," occasionally 

 holding enstatite or bronzite/ mark the derivative forms of the 

 eruptives. 



At New Rochelle masses of amphibolite and actinolite-schist 

 have suffered partial conversion into serpentinoid, and are asso- 

 ciated with coarse black hornblendite, with hornblende in prisms 

 several centimeters in length, hornblende schist, hornblendic 



^ H. B. Patton, Die Serpentin- und Amphibolgesteine nordlich von Marienbad in 

 Bohmen, Inaug. Diss., Wien., 1887, II, 13, 18 ; E. Schulze, Zeits. d. d. geol. 

 Ges., 1883, 433; F. D. Chester, Ann. Rep. 2d Geol. Survey Penn., 1887, 98. 



2T6rnebohm, A\ Jhrb. f. Min., 1877, 383; F. Becke, Tsc/i. mijt. u. pet. 

 Mitth., IV., 1882, 330, 355, 450 ; R. W. Schafer, Tsch. min. u. pet. Mitth., XV, 

 1895, 21 ; F. Bascom, Maryl. Geol. Surv., 1902, Cecil County, 130--131. 



3 Bascom, loc. cit., 126. 



*Dana, Am. Jour. Sci., (3), XX, 1880, 31 ; F. J. H. Merrill, 50th Ann. Rep. 

 N. Y. State Mus., 1896, 40-41. 



