44 NEW YORK STATE MUSEUM 



miles by the stream. Along the vertical walls of the canyon the 

 cliffs rise from 200 to 350 feet displaying the even, regular beds 

 of the rock formations so elaborately and lucidly as to invite the 

 attention of the geological student, while all the attendant phe- 

 nomena of the erosion of the gorge and the history of this great 

 drainage way throughout its many vacillations afford subjects of 

 added interest. The Genesee river crossing the entire State from 

 north to south is the line of most continuous meridional section 

 through the geological formations of western New York. Very 

 naturally then, when the Geological Survey of New York was 

 organized (1836) and the fourth or western district erected (1837), 

 the rock exposures of this stream invited immediate attention. Not 

 only has this trunk stream cut deep into the rock strata but its 

 contributories, Cashaqua creek, Wolf creek, Buck run, Silver lake 

 inlet and Wiscoy creek add other means of completing the details 

 of geological structure so that data are not lacking on every hand 

 to solve the problems of geological history. Public attention and 

 interest has been recently drawn to this region by the erection 

 within its boundaries of a new public preserve — Letchworth Park 

 — the beneficent gift to the people of the State of New York by 

 the Hon. William Pryor Letchworth, to whose munificence and 

 long public service the place will be a perpetual monument. This 

 beautiful property embraces the three cataracts of the Genesee 

 river and the banks adjoining. It is with some satisfaction that, 

 with the aid of Mr Letchworth, we are enabled here to present 

 a special map of this park with its geology given in detail. 



HISTORICAL 



Bibliography 



The rocks and fossils of this portion of the Genesee river section 

 have been the subject of, or have contributed freely to many of 

 the publications of the New York survey. It is not the purpose 

 here to review these in detail as this publication is chiefly designed 

 to explain the accompanying maps. Students will find more or 

 less adequate accounts of the geology and paleontology of the 

 formations involved in the works here cited. 



I The original and fundamental documents upon the region are 

 the Second and Fourth Annual Reports (1836, 1838) and the 

 final report of the geologist in charge of the fourth geological 

 district (1843), James Hall. 



