PREFACE. 



There is probably nothing an author regrets more than 

 to be obliged to publish the results of his labors in an 

 incomplete form. While all fall short of their wishes in 

 this regard, it is not unfrequently the case, that the nature 

 or magnitude of the subject treated renders a near approach 

 to perfection impossible. This is especially true of geolo- 

 gical subjects, and peculiar trials beset those who undertake 

 the preparation of reports upon State Geological Surveys, as 

 they are usually organized. Instead of adopting a definite 

 policy for the work, and making suitable and reliable 

 provision for maintaining it until it shall be completed 

 upon a carefully devised plan, the State Legislatures 

 usually authorize these surveys by special legislative acts, 

 appropriating, at the same time, only sufficient funds to 

 commence them. These acts are not only liable to be 

 repealed by any subsequent legislature, and the work 

 thereby arrested, but it is in constant danger of being 

 suspended by the failure of those legislatures to provide 

 funds for its support. Examples of such legislation may 

 be seen in the copies of laws in the historical part of the 

 introduction on pages eight to twelve. 



Under such circumstances, the person appointed to con- 

 duct the work feels obliged to adopt, not such plans as he 



