1026 



NEW YORK STATE MUSEUM 



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Laona 

 sandstone 



blue shales 

 and thin 

 sandstones 



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So 



Fossils are common in a few of the layers of shale, and, in two 

 rows of large flattened concretions, that are not septaria, there 

 are some finely preserved cephalopods and large lamellibranchs. 

 All these beds are stratigraphically equivalent to the Gardeau 

 of eastern sections, more particularly its upper part, and prob- 

 ably in some degree to the Portage sand- 

 stone horizon. 



This horizon is exposed along Walnut 

 creek below and above the Erie Railroad 

 bridge at Forestville and in a small ravine 

 Y^ mile west of Smith's Mills. 



It is bare at the water level on the lake 

 shore at Correll's point, opposite the vil- 

 lage of Portland. 



Next above the upper row of large con- 

 cretions in the Walnut creek ravine at 

 Forestville, there are 40 feet of soft, light 

 and dark shales in which there are many 

 small concretions and that are succeeded 

 by a flaggy band 10 feet thick, that pro- 

 duces a cascade about 20 feet high by the 

 mill on the north side of Main street. 



Another band of light and dark shales 

 with a few thin flags and small concre- 

 tions, that is about 50 feet thick, overlies 

 the flaggy band and is succeeded by a bed 

 of sandstones and flags separated by thin 

 layers of hard blue shales, that is 22 feet 

 thick, the base of which is the top of the 

 Portage formation on Lake Erie. 



The Laona sandstone (Hall) is an arena- 

 ceous stratum well exposed at the falls 

 in Terry's ravine, 1 mile northeast of 

 Forestville, where brachiopods (S p i r i - 

 fer disjunctus etc.) occur abun- 

 dantly in some of the light colored layers of sandstone, in place 

 in the lower part of the stratum and in several large fallen 

 slabs in the ravine below the falls. 



flags and 

 shale 



dark shale 



with 



concretions 



light and 

 dark shale 



dark slaty- 

 shales 



Fro. 12 Section on Walnut 

 creek from Keech's Corners 

 to sandstone at Corey's mill, 

 Forestville. The upper part 

 from the succession in Terry's 

 ravine. Stations 60, 61 



