36 APPENDIX. 



2. Opinions on Various Subjects, 2 vols. 8vo. This work is 



epistolatory, and was chiefly written in Mexico. It 



embraces reflections on many subjects, but is mainly 



devoted to Political Economy. 



Memoirs in the Journal of the Academy of Natural Sciences 



of Philadelphia: 



1. Observations on the [Geology of the] West India Islands, 



from Barbadoes to Santa Cruz, inclusive. Vol. I, p. 134. 



2. Essay on the Formation of Rocks; or an Inquiry into 



their probable Origin, and their present Form and 

 Structure. Vol. I, p. 261. 

 Memoirs in the American Philosophical Transactions: ' 



1. Observations on the Geology of the United States, ex- 



planatory of a Geological Map. Vol. VI, p. 91. 1809. 



2. The same Memoir, corrected and extended. Vol. I, 



New Series, 1817. 

 Memoirs in the American Journal of Science and Art, con- 

 ducted by Professor Silliman: 



1. Hints on some of the Outlines of Geological Arrangement. 



Vol. I, p. 209. 



2. Conjectures on the probable changes that have taken 



place in the Geology of the Continent of America, east 

 of the Stony Mountains. Vol. VI, p. 98. 



3. Miscellaneous Remarks on the Systematic Arrangement 



of Rocks, and on their probable Origin. Vol. VII, p. 261. 



4. Notice of the Anthracite Region of Pennsylvania. Vol. 



X, p. 205. 



5. Remarks on the Igneous Theory of the Earth. Vol. XVI, 



p. 351. 



6. Geological Remarks relating to Mexico. Vol. XX, p. 406. 



The same periodical also contains many detached Ob- 

 servations, and fragments of letters communicated to 

 the Editor of that work. 



