CONTENTS. XI 



ARTICLE XIII. 



Description and Notices of new or rare Plants in the natural Orders Lobeliaceae, Campanu- 

 laceae, Vacciniese, Ericaceae, collected in a Journey over the Continent of North America, 

 and during a Visit to the Sandwich Islands, and Upper California. By Thomas Nultall. 251 



ARTICLE XIV. 



Observations on the Geology of the Western Peninsula of Upper Canada, and the Western 

 part of Ohio. By William B. Rogers, Professor of Natural Philosophy in the University 

 of Virginia and Henry D. Rogers, Professor of Geology in the University of Pennsylvania. 273 



ARTICLE XV. 



Observations of the Magnetic Dip in the United States. Fourth Series. By Elias Loomis, 



Professor of Mathematics and Natural Philosophy in Western Reserve College. - - 285 



ARTICLE XVI. 



Supplementary Observations on the Storm which was Experienced throughout the United 

 States about the 20th of December, 1836. By Elias Loomis, Professor of Mathematics 

 and Natural Philosophy in Western Reserve College, Ohio- - . - - - 305 



ARTICLE XVIL 



Astronomical Observations, made at several Places in the United States. By J. N. Nicollet. 30? 



ARTICLE XVIII. 



Observations of Encke's Comet, at the High School Observatory, Philadelphia, March and 



April, 1842, with the Fraunhofer Equatorial. By Sears C. Walker, and E. Otis Kendall. 311 



ARTICLE XIX, 



Observations of the Magnetic Dip, made in the United States, in 1841. By J. N. Nicollet. 317 



Donations for the Library and Cabinet. -------,.-- 325 



