72 



TRANSACTIONS OF THE 



[Jan. 23 



strongly resembled the norites of the Cortland Series,* near 

 Peekskill, and those of the exposures near Baltimore. f Its 

 great freshness gave the impression at the time that it was an 

 abnormal Triassic diabase, and the discovery was held in 

 abeyance until it would be possible to visit the region itself. 

 Meantime Messrs. Campbell and Brown| announced the hyper- 

 sthene- diabase of Virginia and recorded its discovery in western 

 New Jersey and eastern Pennsylvania, b}^ Mr. Darton, so that 

 although it had been learned that Van Artsdalen's quarry is in 

 a little exposure of limestone, in the Archaean strip that crosses 

 southeasten Bucks Country it was inferred that an erratic had 



TRIASSiC t GNEISSES 

 [5J 



POTSDAM 

 i/i M I L E 



Determinations of numbered specimens of map. 1 5 Limestone and 

 inclusions of silicates. 6. Decomposed gneiss. 7. Dark gneiss. 

 8. Green schist. 9. Decomposed gneissic gahbro? 10. Quartzose 

 gneiss. 12. Mica schist. 13. Mica schist. It. Quaitzite. 15. Coarse 

 " ~ ■ " ■■ 17. Coarse gneiss oi granite. 18. 



2-2. Gabbro. 23. 



gneiss. 16. Diabase boulder. 

 Gneiss. 20. Conglomerate. 21 

 Pegmatite. 26. Arkose. 27. Quartzite 



Schistose gneiss. 



*See J. D. Dana. Amer. Jour. Sci. Sept. 1880, p. 197. G. H. Williams, idem, 

 -Feb. 1887. p. 135, Mar. p. I'Ji. 



t G. H. Williams, Bulletin 28. U. S. Geol. Sui-vey. 



t H. D. Campbell and W. G. Brown, Bull. Geol. Soc. of Amer. ii. 339, 1891. 



