vfALCOTT.] PROBLEMS FOR INVESTIGATION. 383 



rian (Ordovician) rocks. This, apparently, will have to be based upon 

 the paleontological evidence, as the strati graphic series is unbroken 

 and there is a gradual gradation between the schists or slates and the 

 limestone by the intercalation of calcareous beds in the shales until the 

 latter predominate and form the limestone series. This investigation 

 can probably be best carried on in York and Adams Counties and the 

 western portion of Lancaster County. 



(3) The relation of the quartzite to the subjacent rocks also requires 

 careful investigation all aloug the line of contact of the two terranes. 



(4) Another problem that requires investigation is whether the Pri- 

 mal slates and schists graduate into limestones to the east and north- 

 east of Lancaster County, or whether there is a line of uncomformity, 

 by non deposition, between the quartzite and limestone in Chester, 

 Berks, Bucks, Lehigh, and Northampton Counties. In other words, 

 whether the portion of the Cambrian section as found in York and 

 Adams Counties is absent in the counties to the northeast, or if it be 

 represented by the lower portion of the limestone series. 



Virginia. — The knowledge of the stratigraphic position of the rocks 

 referred to the Cambrian, in Virginia, is in a much more satisfactory 

 condition than that of Pennsylvania. It is desirable, however, that 

 attention be given to: 



(1) The changes in the character of the sedimentation from the Ten- 

 nessee line north to the Potomac, and also the chaugesin the character 

 of the sediment between the shore deposits of sand and conglomerate 

 and the off shore deposits of shale and calcareous matter. 



(2) The paleontologic evidence of the geologic age of the strata re- 

 ferred to the Cambrian, is very defective, and investigation in this line 

 should be made throughout the State. 



North Carolina. — The problems to be considered in North Carolina 

 are: 



(I) The section along the French Broad, so as to determine the age 

 of the strata and, if Cambrian, ascertain the stratigraphic position of 

 the limestones, shales, sandstones, and quartzite to each other and to 

 the sections of eastern Tennessee. 



• (2) About the same problem is presented in the rocks on the line of 

 the Hiwassee section, in the southwestern portion of the State. 



Tennessee. — The questions requiring investigation in Tennessee are: 



(1) The stratigraphic relations of the Chilhowee formation to the 

 Knox sandstone and Shale series. 



(2) The relations of the eastern shore deposits to the off-shore deposits 

 westward of the pre-Cambrian rocks. 



(3) The collection and the study of the faunas of the Chilhowee and 

 Knox-shale formations. 



(4) The geographic distribution of the strata and the vertical range 

 of the faunas. 



Georgia and Alabama. — The entire Cambrian section of Georgia and 

 Alabama needs to be worked out stratigraphically, especially the rela- 



