INTRODUCTION. 



Ever since the publication of the New York State Geological 

 Reports, Eighteen Mile Creek and the shore of Lake Erie 

 has been classic ground for the stratigraphist and pale- 

 ontologist. Probably no other locality is so frequently 

 referred to in the literature of the Middle Devonian of this 

 country, as is this, under one of the following names: 

 "Eighteen Mile Creek," "Shore of Lake Erie," "Hamburgh, 

 Erie County," "West Hamburgh," or " Hamburgh-on-the- 

 Lake." 



The exposures in this area represent a continuous section, 

 from near the base of the Middle Devonian to near the top 

 of the Upper Devonian, and the total thickness of these beds 

 is only a few hundred feet. Furthermore, the beds exposed 

 represent deposits made at a considerable distance from the 

 land, which was the source of the mechanical sediment. The 

 conditions of the water in this area were consequently more 

 uniform, and the deposits less complex than was the case in 

 regions nearer to the old shore line. For these reasons the 

 study of the Middle and Upper Devonian beds is prohtably 

 commenced in this locality. The sections furthermore, on 

 account of the limited thickness of the formations, enable 

 the student to take a more comprehensive view of the whole 

 series than is possible farther east, in which direction the old 

 shore-line is to be sought. 



Structure. — It should be borne in mind, that the gorge of 

 Eighteen Mile Creek is simplv a deep, broad trench, cut into 

 the strata, which before the cutting of the gorge, continued 

 without interruption. In the walls of the gorge, where not 

 obscured by vegetation, the cut edges of the strata appear 

 on opposite sides, the portion of the beds cut out between, 



