THE NORM AN SKILL GRAPTOLITE FAUNA 273 



typical Trenton limestone of New York, or even to a position below 

 the middle. 



Dr. Emmons long ago expressed the belief that the formation 

 extended through to Virginia, but very little is reported of it from 

 the south. Prof-essor E. A. Smith, state geologist of Alabama, 

 reports a small fauna of about eight species occurring in calcareous 

 shale associated with Trenton limestone, which he believes to be 

 upper Trenton. This find, however, could demonstrate nothing 

 more than the general fact of the Trenton age of the Normanskill 

 fauna. Stratigraphic proof of the age of the formation has not 

 been found in New York for the reasons stated by Ruedemann, 

 that the whole mass of rocks, which contains Trenton, Utica, and 

 Lorraine beds in similar lithologic development, is in New York as 

 well as in Canada cut off from the neighboring terranes by extensive 

 faults, thus apparently frustrating all attempts at a stratigraphic 

 solution of the problem. As the primary object of this preliminary 

 note, in addition to calling attention to the many species of grap- 

 tolites occurring here, is definitely to locate on stratigraphic grounds 

 the exact position of the formation containing this fauna, a descrip- 

 tion of the relevant portion of the section is given. 



The Cambro-Ordovician section under investigation is in 

 Roanoke County, Virginia, about 11 miles north of Salem, and 

 extends from the top of Catawba Mountain northward across 

 Catawba Valley to the foot of North Mountain, a distance of 

 about 6,000 feet. This section is characterized by the unusual 

 occurrence of all the strata from top to bottom in regular chrono- 

 logic order, there being no faults or folds to disturb the natural 

 sequence. Furthermore, the strata are most favorably disposed 

 for observation, dipping at an angle of 45° on Catawba Mountain, 

 and gradually rising to 70° in the valley. The new state road just 

 being graded down the side of the mountain and across the valley 

 exposes every stratum in the section from the top of the Medina 

 on the south face of Catawba Mountain to the base of the Cambrian 

 at the foot of North Mountain. 



At the latter point there is a fault bringing the Carboniferous 

 in conjunction with the Cambrian, which terminates the section. 

 The section therefore includes every stratum from the top of the 



