20 NEW YORK STATE MUSEUM 



Tichenor limestone 



This name is applied to a stratum of crinoidal limiestone ij to 

 2 feet thick that is persistent toward the east for more than a 

 hundred miles, maintaining the same general character and varying 

 but slightly in thickness. It has been commonly known as the 

 Encrinal limestone, a name applied to it by Hall in 1839. Since 

 the latter term, in the Genesee valley and Canandaigua lake sections, 

 has been applied by others to limestone layers of similar character 

 but occurring at distinctly different horizons, confusion had arisen 

 and a more distinctive appellation for this stratum become impera- 

 tive. It has therefore been designated Tichenor limestone' from 

 its typical exposure in the ravine at Tichenor Point on Canandaigua 

 lake and along the shore toward the south. 



It is usually a single compact layer, hard and durable, but at 

 some outcrops the upper or lower part is somewhat shaly, and in the 

 cliff on Smoke's creek near Windom it is separated in two layers, 

 the lower one 1 5 inches and the upper 9 inches thick. 



This stratum emerges from the waters of Lake Erie near the 

 mouth of Pike creek, 5 J miles southwest from the southern limit 

 of this quadrangle on the lake shore, and forms a conspicuous band 

 in the stratigraphy of the south shore at I die wild and Wanakah 

 cHffs. 



At Hamburg-on-the-lake it passes half a mile, and at Athol 

 Springs 200 yards east of the railroad; at Big Tree it is exposed 

 at 640 feet above tide in the railroad cutting near Rush creek and 

 on the banks of the stream near the farmhouse above. At Windom 

 it appears at 680 feet above tide in the banks of Smoke's creek for 

 some distance near the station and crosses the bed of the stream 

 ^ mile further up. 



It is also exposed on the east branch of Smoke's creek, i mile 

 southwest from Reserve at the top of a cascade 30 feet high, south- 

 east of Reserve along a small brook that empties into Cazenovia 

 creek. 



The Tichenor limestone carries an abundant fauna. Dr Grabau's 

 list contains the names of 60 species occurring in this region, of 

 which the following are the more abundant or striking forms: 

 Phacops rana {Green} S. mucronotus Hall 



Diaphorostoma lineatum (Hall) Vitulina pustulosa Hall 



Modiomorpha concentrica (Conrad) Centronella impressa Hall 

 Rhipidomella vanuxemi Hall Cryptonella planirostra Hall 



R. penelope Hall Tropidoleptus carinatus (Conrad) 



Spirifer granulosus (Conrad) Favosites hamiltoniae Hall 



'N. Y. State Mus. Handbook ig. 1903. p. 22. 



