Bemarks on the Trenton Limestone of KentuGky. 147 



Danville Junction, where we have the Black Shale at the surface. At 

 the level of the top chord of High Bridge, and a few feet higher, 

 may be identified that portion of this section most like the Glade Lime- 

 stone of Safford, and furnishing a surface of country upon which 

 cedars grow. It is not difficult to recognize above this a distinct 

 division which corresponds to the Carter's Creek Limestone. Above 

 this is a bed filled with fossils of the very highest interest, many of 

 which are species found in Safford's Orthis Bed, Mdiile others are species 

 not collected outside of Canada, until 1 found them here. Still above 

 this is the ragged mass of thin-layered limestone, forming the upper 

 part of the section. All these divisions may be passed in review by 

 going south from High Bridge, along the railroad to the top of the 

 divide this side of Burgin, and three and one half miles beyond the 

 Kentucky river. 



I have referred the above portion of this section to the Orthis Bed 

 for two reasons. It abounds in silicified specimens of 0. testudinaria, 

 and it is composed of a silicified limestone that weathers into a red soil, 

 like that of its Tennessee equivalent where I have studied it in Maury 

 county. The rock is a siliceous limestone, with a sandy matrix and 

 carbonate of lime cement. The latter readily dissolves, leaving a some- 

 what sand}' soil, which is, in many cases, strewn with chert and silici- 

 fied fossils in a fine state of preservation. 



The following list contains many of the species collected in this part 

 of the section: A few are yet unidentified. (7aZ?/mme?ie species not 

 determined. Leperditiafahulites, Conrad; Colpoceras virgatum^Jl?i\\\ 

 GJyptocrinus prisons, Billings; Blastoidocrinus carcharidens^ Bill- 

 ings; Hyhocrinus tumidus^ Billings ; Hybocrinus conicus, Billings; 

 Amygdalocystites florealis, Billings; Amygdalocystites radiatus^ Bill- 

 ings; Hyhocystites problematicus^ Wetherby, herein described; 

 Cypricardites ohtusus, Hall; G. cordiformis^ Billings; Cypricardites, 

 sp. ined., Conularia quadrata, Walcott; BeceptacuUtes, sp., exhibiting 

 well man\^ of the characteristic points of structure so ably discussed 

 by Mr. Billings, but^not identified with any described species; O. 

 pec tinella, Conrad; 0. ^^er-yeto, Conrad ; O. trlcenaria, Conrad; U. testu- 

 dinaria^ Dalman; LeptcBua sericea^ Sowerby; Orthis lynx, Eichwald; 

 Strophomena incrassata, Hall; Cyrtolites ornatus^ Conrad; Murchi- 

 sonia milleri. Hall; Petraia aj:>er^a, Billings; Streptelasma profundu7n, 

 Hall. 



This list of fossils is sufficient to identify this part of the section 

 with the Trenton beyond any question whatever, and fixes the fact 

 that the three hundred and fifty or.more feet of heavy-bedded lime- 



