6 PREFACE. 



In preparing this report, I have in reality drawn it up in two parts, though this 

 is not distinctly stated. The first part embraces a general description of all the 

 rocks, accompanied with an illustration of many of the principal phenomena 

 which they disclose. In the second part, or the geographical division of the 

 work, [ have noticed the peculiarities which are furnished in different parts of 

 the district. In consequence of this method, I may sometimes have been too 

 minute in drawing up my description, and may have repeated the same fact in 

 several jilaces. 



It becomes necessary to notice, in this place, what may appear as discrepan- 

 cies of some parts with others, particularly in relation to the nomenclature. I 

 jjroposed the words New-York Transition System, as the name by which the 

 rocks should be desiirnated. I had previously used the same term ; and in fact, 

 having a predilection for the word ti-ansilion, I early proposed the above desig- 

 nation for the New- York rocks. Subsequently it was proposed to strike out the 

 word trnnsition, leaving the simple ajipellation, New-York System, which, being- 

 shorter, I considered a better name, and hence it was adojoted and generally 

 used ; but this change was not proposed until the whole of my general account 

 of the rocks was printed. Other changes, too, have been made in the progress 

 of the work, not contemplated in the commencement: several illustrations have 

 been added, particularly the wood-cuts of some of the characteristic fossils, which 

 were not determined on until too late to employ them in the general description 

 of the rocks. 



Without attempting to sum up all the results of the Survey of the Second 

 District, I may with propriety state generally, that the rocks, their relations and 

 mineral contents, have been determined over an area of ten thousand square 

 miles ; and their geographical boundaries, lithological and palisontological cha- 

 racters, have been ascertained with great exactness. That many interesting 

 facts, however, are yet to be discovered, I have no doubt. The field, in fact, 

 may be considered as only now prepared for investigation, or opened for a more 

 successful exploration ; and I hope yet to be able to complete a series of obser- 

 vations, which I have had opportunity merely to commence, particularly those 

 in relation to drift and diluvial action, as well as others in relation to the presence 

 of ores. 



In rendering acknowledgements due to those who have promoted the objects 

 of the Survey, they are due first to both of the Chief Magistrates who have suc- 

 cessively filled the Chair of State during its progress, not only for oflicial acts 



