24 THE DEVONIAN AND CARBONIFEROUS. [bull. 80. 



In 1819 the American Geological Society was formed. 1 It was incor- 

 porated by the State of Connecticut and provisionally located in New 

 Haven, and the first meeting was held in the philosophical room of 

 Yale College, New Haven. 



The Geological Society continued in existence for several years and 

 gradually came to an end. 2 



It is evident from the honor bestowed upon William Maclure that in 

 the first quarter of the century he was regarded as the most learned 

 American geologist. In 1819, when the American Geological Society 

 was started in New Haven, he was elected its first president. In a 

 note at the foot of page 360, volume n, of the Silliman Journal, where 

 a donation from him to the American Geological Society is referred to, 

 he is described as a gentlemen who " has, in person, examined the 

 geology of almost every portion of Europe as well as of the civilized 

 portions of America. He has visited several countries repeatedly, and 

 has inspected most of the interesting localities of minerals in Europe 

 and America." 



When we remember how few of the present facilities for travel and 

 communication with foreign lands were existent in 1820, when this was 

 written, some idea can be formed of the great influence such a man 

 must have exerted over the opinions of American geologists. 



W. B. Stilson, in a sketch of the geology and mineralogy of a part of 

 the State of Indiana, briefly described the geological formations of the 

 State, and referred them to the " secondary rocks." This was a cor- 

 rect correlation following Maclure's classification ; the mistake, as be- 

 fore noted, was in the standard scale. 



In 1820 Prof. Amos Eaton published u An Index to the Geology of 

 the Northern States." 3 The observations recorded in his book are 

 almost entirely the result of his own personal experience. He writes 

 in the preface, page vi: " With respect to the theoretical part, as far as 

 I have given in to any theory it is to that of Werner, with the im- 

 provements of Cuvier and Bakewell." 



He recognized eighteen strata in order from the bottom upward, 

 which he grouped into five classes. These were as follows: 



I. Primitive class 



Strata. 



1. Granite. 



2. Gneiss. 



3. Hornblende rock. 



4. Mica slate. 



5. Talcose rock. 



6. Granular limestone. 



1 Am. Jour. Sci., vol. 2, page 139. 



2 Prof. Dana informs me by letter, October 30, 1888, that by consultation of the records of the society 

 in Tale College library he ascertained that the last meeting of the society was held in 1826, and the 

 last member, E. Leffingwell, died in New Haven during the year 1888. Isaac Lea was a member of 

 the society, and when he died there was but one member of the society still living. In the earlv num- 

 bers of the American Journal of Science frequent references are made to the reception of books and 

 specimens by the society. 



» Second edition, 286 pages, 12mo, Troy, New York. 



