CHAPTER I. 



THE GEOLOGY OF EIGHTEEN MILE CREEK. 



General Description. — Eighteen Mile Creek belongs to the 

 St. Lawrence drainage system, its waters being tributary to 

 the basin of Lake Erie. The course of the stream lies wholly 

 within the southern portion of Erie County, N. Y., its most 

 important sections, from a stratigraphical point of view, 

 lying within, or on the borders of the township of Hamburgh. 



Taking its origin in the southern uplands of the count}', it 

 flows northward and westward, receiving numerous tribu- 

 taries, until its united waters are poured into Lake Erie at a 

 point just eighteen miles south-west, along the lake shore, 

 from the former village of Black Rock, at the head of the 

 Niagara River, a site now included within the limits of the 

 city of Buffalo. 



The general direction of the stream in the last two miles of 

 its course is north-westerly, and for this distance it forms 

 the boundary line between the townships of Evans and 

 Hamburgh. For the greater part of its course the stream 

 flows through a rocky gorge, the walls of which, in many 

 places, rise to a perpendicular height of a hundred feet or 

 more. 



The strata exposed in the gorge of the main stream and 

 its tributaries all belong to either the middle or upper part 

 of the Devonian series. The lowest beds found in the gorge 

 are exposed at the mouth of the main stream and belong 

 near the base of the Hamilton stage. The highest beds 

 exposed in the upper portions of the gorge probably belong 

 to the lower Chemung, i. e. the Portage sandstone, but this 

 is simply a matter of inference as the upper gorge and 

 branches have not' been examined. 



The lower portion of the gorge is wider than other parts. 

 This is to be accounted for by the presence of the softer 

 Hamilton shales, which first become prominently exposed 



