60 GEOLOGY OF ERIE COUNTY 



Gardeau Shale. 



Lying in the upper Portage beds and limited below by the 

 Dunkirk shale is the thick mass of the Gardeau shales. They 

 have derived their name from their exposure at the former Indian 

 Reservation at Gardeau on the Genesee river. Originally the 

 name was applied by Hall to that portion of the Portage group 

 lying above the Cashaqua shale and below the Portage sandstone. 

 This great mass of rock has been subdivided by Dr. Clarke and 

 the name Gardeau restricted to those shales and sandstones in 

 western New York lying below the L,aona sandstone, and in the 

 Canandaigua exposures, limited below by the Grimes sandstones 

 which seem to be the eastern extension of the Dunkirk. In 

 western New York there is no definite line of demarcation at the 

 bottom of these formations unless it be the Dunkirk shale. But 

 Hartnagel in his classification of the rock formations has included 

 the Dunkirk in the Gardeau. This makes the Gardeau in 

 western New York include all the arenaceous and black shales 

 and sandstones lying between the bottom of the Dunkirk shale 

 and the L,aona sandstone. The Dunkirk shale is distinct enough 

 to warrant our excluding it from the Gardeau. 



The Gardeau shale thus defined, excluding the Dunkirk 

 shale which has been described in previous pages, comprises a 

 thick deposit of sandy shales and thin sandstones of which 

 Luther described 350 feet in Walnut creek, Chautauqua county. 

 The formation includes layers of gray shale, without cleavage 

 planes, not fissile but breaking into irregular lumps and usually 

 stained brown on exposed edges. Other shales are black, fissile, 

 and rust stained, with cleavage planes. Many beds are made up 

 of alternating laminae of gray, sandy shale and sandstone. In a 

 cliff the exposed shale frequently takes on a pink or red tinge. 

 The sandstones are in thin layers from a fraction of an inch to a 

 foot in thickness. Concretions are numerous and in some beds 

 of rather large size. 



The Gardeau shale forms cliffs along Cattaraugus creek from 

 Versailles to Springville. A typical section may be seen in the 

 cliff about three miles above Versailles. Some excellent sections 

 are exposed at Gowanda and just above at the mouth of a small 

 brook that joins the creek from the south. Another excellent 

 section may be seen in the south branch of Cattaraugus creek 

 about three miles south of Gowanda on the road to Otto. The 



