35O PIONEERS OF SCIENCE IN AMERICA. 



heard the excited cry, " I've got it ! I've got it ! " and out 

 rushed the geologist, bearing triumphantly a muddy fragment 

 of rock. He had secured a piece of evidence in support of his 

 Taconic System. 



In 1836 a law was passed providing for a geological survey 

 of the State of New York, and in the organization of the staff 

 for carrying on that work Dr. Emmons was appointed by Gov- 

 ernor Marcy to the charge of the second district, which in- 

 cluded the northeastern counties of the State. This district 

 was chosen by Dr. Emmons as a field more especially interest- 

 ing to him on account of its mineral localities and minerals, 

 and giving him a field more congenial to his tastes and ex- 

 perience. He made the public acquainted with the Adiron- 

 dack region and named its principal mountains. In 1837 he 

 named, described, and classified the celebrated Potsdam sand- 

 stone. Among the other rocks and divisions to which he gave 

 a name or a place in geology are the Chazy limestone, black 

 marble of Isle la Motte, Lorrain shales, Champlain group, 

 Ontario group, Helderberg series, and Erie group. Dur- 

 ing the progress of this survey, also, he made the impor- 

 tant discovery that is most closely associated with his 

 name. In 1842 he pointed out a great system of stratified 

 rocks under the Potsdam, which he called the Taconic 

 System. This announcement brought upon him a storm of 

 contradiction and ridicule, and for a time he was scien- 

 tifically ostracized. Subsequent discoveries by the Canada 

 survey, and by Barrande, in Bohemia, however, as well 

 as the investigations of later eminent geologists, have 

 completely sustained him. In propounding the term Ta- 

 conic* System Prof. Emmons was following the instruc- 

 tion and views of his teacher, Prof. Amos Eaton, who promul- 

 gated his opinions regarding the age of these rocks in his 

 lectures at Williams College from 1817 onward; and subse- 

 quently in his lectures at the Rensselaer School to the end of 

 his life, although never having published any satisfactory ac- 

 count of the relations of these rocks to the formations above or 

 below them. 



Two years later Dr. Emmons described the primordial 

 fauna, thus preceding the celebrated discoveries of Barrande, 



* From the Taghkanic Mountains. 



