ELISHA MITCHI:CLL SCIENTIFIC SOCIETY. 70 



localities. Durinj^' the summer of 1893, Dr. George H. 

 Williams in company, with Prof. J. A. Holmes, State 

 Geoloo-ist of North Carolina, made a reconnaissance trip 

 throug-h Chatham and Orano'e counties, the results of 

 which are included in Dr. Williams' paper on the distri- 

 bution of the ancient volcanic rocks in eastern North 

 America.' He says: "In a drive from Sanford to Chapel 

 Hill an abundance of the most typical ancient lavas, most- 

 1}^ of the acid type, was encountered. On the road from 

 Sanford to Pittsboro purple felsites and porphyries show- 

 ing spherulitic and beautiful flow structures, and accom- 

 panied by pyroclastic breccias and tulTs, were met with 

 two miles north of Deep river, and were almost continuous- 

 ly exposed on Rocky river Here devitrified acid o-lasses 

 with chains of spherulitic and eutaxitic structure were 

 collected, while beyond, as far as Bynum on Haw river, 

 four miles northeast of Pittsboro, the only rocks seen 

 were of the same g-cueral character. On the farm of 

 Spence Taylor, Esq., in Pittsboro, a bright red porphyry 

 with flow lines is exposed in so altered a condition that 

 it can easily be cut into any form with a knife, thoug-h it 

 still preserves all the details of its structure. * * * 

 Three-quarters of a mile beyond Pittsboro, on the Bynum 

 road, there is a considerable exposure of a basic amygda- 

 loid. South of Hackney's Cross Roads there are other 

 excellent exposures of ancitmt rhyolite with finely devel- 

 oped spherulitic and flow structures. * * =i< Another 

 locality in the volcanic belt was visited on Morgan's run, 

 about two miles south of Chapel Hill. Here are to be 

 seen admirable exposures of volcanic flow and breccias 

 with finer tuff deposits, w^hich have been extensively 

 sheared into slates by dynamic ag-ency. Towards the 

 east and north these rocks pass under the transgression 

 of Newark sandstone. * * * From still another local- 

 ity at the Cross Roads near the northern boundary of 



1 Jour. GeoL, vol. 2, 1894, pp. 1-32. 



