iig Midway Stage 5 



Aim and scope of this work. 



The first or basal stage of this series is the Midway, and it is 

 to this that we call attention in our present work. Part I is a 

 brief sketch of the geological features of this terrane, as inter- 

 preted by former authors and by the present. These statements 

 we believe will materially assist the beginner to understand cer- 

 tain passages found in different publications now quite at vari- 

 ance or diametrically opposed to each other. Part II is intended 

 to include original descriptions, localities, whereabouts of types, 

 figures, etc., of all well authenticated molluscan species known 

 from the Midway. 



Farther on we shall have occasion to call attention to the fact 

 that between the basal Eocene deposits and the uppermost Cre- 

 taceous there is in this section of the country a decided break, 

 both stratigraphic and faunal so that not one species is known 

 certainly to have crossed from one formation to the other. At 

 or immediately above this line an entirely new fauna makes its 

 appearance upon the scene; whence it comes we cannot say, nor 

 does it particularly concern us here, but its many subsequent 

 modifications, and its decadence, and final merging into newer 

 forms we hope to trace, if but imperfectly, during the following 

 decade. With this evolutionary study we shall of necessity cull 

 over, select out and re-publish all important paleontological 

 facts heretofore published and hence do away with the greatest 

 impediment to progress in our marine Tertiary faunas, namely, 

 the scattered and almost Inaccessible state of the literature. 



Collection of fossils, field notes, etc., on which this 

 work is based. 



The Cornell University collection and the collectors' notes. — In 

 the spring of 1895 the Trustees of Cornell University generous- 

 ly appropriated the sum of $400 to be expended in geological 

 and paleontological research in the Tertiaries of our Gulf and 

 Atlantic coast States. This sum was for defraying the field ex- 

 penses of the writer and one assistant who were to volunteer 

 their services during the following summer vacation in the field 

 specified. Accordingly Mr. W. S. Hubbard and the writer left 

 Ithaca in the latter part of June, and after visiting west Ten- 

 nessee, northern and central Mississippi, central Alabama and 

 western Georgia, returned North in the latter part of August. 

 The collections made during this interval furnish what may be 

 called the nucleus of the present work. They include not only 

 fossils but sections and photographs of the more interesting or 

 important localities. These may all be found catalogued and 



