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No. LXX. 



Account of Chrystallized Basaltes found in Penn- 

 fylvania — By Thomas P, Smith. 



Readja.i.'T^HE firft placc at which I found thefe bafaltes 

 18. 1799- X was on the Conewaga hills, caft of the Sufque- 

 hanna and about half a mile to the north of Elizabeth-town. 

 They are here to be found in confiderable quantities, both 

 chryftallized and amorphous — The chryftals are generally 

 tetrahedral and of a very fine grain. There are great mafles 

 of it lying about amorphous, but It generally has a very 

 ftrong apparent tendency to chryftallize. — As I travelled in 

 the ftage I had not an opportunity of examining this place 

 as minutely as I could have wifhed. It is I think well wor- 

 thy the attention of a minerallurgift whofe time will permit 

 and talents enable him to explore it accurately. 



On my return from Northumberland by a different rout, 

 I again found them at Campbell's town ; they are here evi- 

 dently a lateral branch of the Conewaga hills', and are fcat- 

 tered on the furface in the greatefl: profulion. 



Soon after this ! met with them on recrofling the Cone- 

 waga hills at Grubb's mines : as I now-travelled in a private 

 carriage, I had a much better opportunity of examining this 

 part than near Elizabeth-town. At the foot of thefe" hills 

 Dr. Barton found a great quantity of regularly chryf- 

 tallized ^TrtwVr, the predominate figure tetrahedral, higher 

 up the chryfi:al!ized bafaltes appeared ; and what in my opi- 

 nion is a ftrong corroborating proof of their Neptunian 

 origin, they v;ere interfperfed with large maifes of brcchia 

 compofed oifiUcious pebbles evidently rounded by friaion 

 imbedded in the red free-ftone of our mountains. 



From 



