22 NEW YORK STATE MUSEUM 



Tichenor limestone 



A stratum of hard bluish gray hmestone lo to 14 inches thick over- 

 lies the Ludlowville shale at all exposures of this horizon from Onon- 

 daga county to Lake Erie, showing little variation in character though 

 its fossils are much more abundant and better preserved at some ex- 

 posures than at others. 



It usually is composed largely of crinoid stems, and for this rea- 

 son received the designation Encrinal limestone from Hall in his 

 annual report on the geology of the Fourth District (for 1838) 1839 

 and by which it was known until the term Tichenor limestone was 

 applied to it by Clarke in State Museum Handbook 19, from its 

 favorable exposure in Tichenor gully on the west shore of Canan- 

 daigua lake. In the southern part of the Genoa quadrangle, in 

 addition to the hard layer, there are 2 to 3 feet of hard calcareous 

 shale and thin limestones that clearly belong to this division. 



The most southern exposure of the Tichenor limestone in the 

 Cayuga lake valley is on the east side of the Lehigh Valley Railroad 

 25 rods south of the cement factory at Portland or Shurger point. 

 It is here a calcareous band 2 feet 9 inches thick, the upper part 18 

 inches thick being quite hard and compact and the remainder, except 

 a few thin layers, quite shaly. 



There are two thin limestones of similar character 5 and 7 feet 

 higher, and the Ludlowville shales below are highly calcareous and 

 fossiliferous. In Shurgers glen the hard layer is exposed at the top 

 of the falls 50 feet above the lake level and in some places contains 

 masses of crinoid stems 8 to 10 inches thick. 



It appears 45 feet above the lake level in a small ravine ^s mile 

 north of Portland and in the north bank of Salmon creek at Myers 20 

 feet higher than the lake. 



It is above lake level for a few rods at the mouth of Willow creek 

 on the west side of the lake, but is submerged from that point to 

 Kidders where it emerges and rising rapidly toward the north and 

 west produces the lower falls in the ravines of Sheldrake, Groves 

 and Barnum creeks. 



On the east side it emerges at Atwaters and is well exposed along 

 the railroad and in several ravines between Atwaters and King Ferry. 

 In the ravine at the latter place it forms the crest of the second falls, 

 30 feet above the lake, and is also at the top of high falls in three 

 ravines near the lake north of King Ferry. 



It forms the crest of the falls in the ravine of Paynes creek and 

 rising toward the southeast, appears in the bed of the stream several 

 times between the falls and the forks of the creek. 



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