432 T. G. White—Original Trenton Rocks. 



Watertown, N. Y., and on Lake Champlain, was found here at 

 about 55 feet. In the Trenton Falls section Orthoceras and 

 Crinoid fragments are most abundant in the lower portion. 

 Tellinomya dubia marks a zone at 18 feet, Bucania puncti- 

 frons at 40 feet, while at 235 feet is a zone notable for its 

 numerous well-preserved examples of Rafinesquina deltoidea, 

 A limestone resembling a cement rock, with graptolites, Conu- 

 laria and Amhonychia heliistriata, occurs at 139 feet. Seventy- 

 nine species are recorded in all in the faunal lists of the various 

 beds. Platystrophia hiforata^ Rafinesquina alternata^ Plee- 

 tamhonites sericea^ Asaphus jplatycephalus^ Calymene senaria^ 

 and Ceraurus jpleurexanthemus are prevalent throughout the 

 section. RhynGhotrema incequivalvis, Rellerophon hilohatuSy 

 NuGula levata^ Murchisonia gracilis^ and M. niilleri, and 

 Trinucleus concentricus occur principally in the lower layers. 

 In the more shaly layers, various species of Lingula occur 

 throughout, and oue apparently new species was discovered. 

 Trematis seems to be confined to the lower strata, while Crania 

 trentonensis first appears toward the top. Various typical 

 Trenton species of frequent occurrence in other localities, such 

 as Cliniacograjptus, Solenopora compacta^ Orthis occidentalism 

 O. tricenaria, 0. subquadrata, Leptcena rhoniboidalis, Rhyn- 

 ( I chotrema capax^ Cyclospira hisulcata^ were not found among 



the material collected, indicating that they are at least not 

 abundant, if indeed they occur in the region. 



The relative position in the stratigraphy of all the genera 

 previously mentioned has been found in general to be similar 

 in the Lake Champlain valley, and the species lacking at 

 Trenton Falls are lacking there also, apparently indicating 

 comparatively uniform life distribution around the Adirondack 

 island during the period of Trenton seas. 



Geological Department, Columbia University. 



