XXIII 
To Drs.J. H. Mc. Gregor and H.F.Osborn, of the American Museum 
of Natural History, New York, the Commission is under many obligations 
for the valuable memoir published as Part II of this volume, on the inter- 
esting reptilian fossil, Mesosaurus brasiliensis. 
To Dr. John M. Clarke, State Geologist of New York and to Dr. Geo. 
P. Merrill, Head Curator of Geology of the National Museum, Washing- 
ton, D. C., the Commission is especially indebted for their very inte- 
testing reports on Devonian fossils and igneous rocks, respectively, pub- 
lished in this report. Also to Drs. Girty and Stanton of the U. S. Geolo- 
gical Survey for determinations of fossil animal remains. 
Finally, to Dr. David White, the distinguished paleobotanist of ‘the 
National Museum, and the U. S. Geological Survey, Washington, D. C., 
the Commission is greatly indebted for his arduous «labor of love» in 
the preparation of Part III, on the fossil plant collections. 
No one realizes better than the writer the preliminary and provisional 
nature of much of the geological work in this report, especially that con- 
cerning the rocks lying above the Rio Bonito or Coal Measures beds, 
upon which so little time could be expended. 
The writer is aware of these imperfections, and fully expects that fu- 
ture observers with better opportunities, will detect many errors in the 
work and conclusions herein recorded, but this is inevitable in all pioneer 
work, and cannot be avoided unless the geologist should fail to publish 
any conclusions whatever concerning which there can be any doubt. 
It is hoped that the genuine contributions to the science of geology and 
paleontology recorded in the excellent memoirs of J. H. Mc. Gregor and 
David White in Part II and Part III of this Report will in some measure 
atone for the imperfections and errors discovered in Part I of this volume. 
A list of authors upon the geology of South Brazil, from some of 
whose works the writer has received much aid, is given in Apendix HI 
at the end of this volume. 
