382 THE CAMBRIAN. [bull. 81. 



of New York. They differ in the northern portion, owing to the vary- 

 ing character of the sediment. Some of the questions are — 



(1) The relatiou of the lower band of limestone ("Red sandrock"), 

 bearing the Olenellus fauna, to subjacent rocks. 



(2) The relation of the shore deposits, forming the " Granular Quartz" 

 on the western slope of the Green Mountains, to the off-shore deposits, 

 forming the limestones ("Red Sandrock") and shales (Georgia, etc.) 

 carrying the Lower and Upper Cambrian faunas, in northern Vermont. 



(3) The change in character of the sedimentation of the Cambrian 

 rocks from the northern to the southern part of the State and their 

 transition into the shale and slate series of New York. 



(4) The determination of the extent of the range of the Cambrian 

 fauna in the limestones of the " marble belt" in southern Vermont and 

 the relations of these beds to the subjacent Cambrian strata on the 

 western side of the " marble belt." The latter involves the question 

 of the relation of the slates and shales carrying the Olenellus fauna and, 

 in part, the base of what may be a portion of the Middle Cambrian 

 fauna to the limestones. The working out of the complicated struc- 

 tural geology and the identification and mapping of all the formations 

 will be required in the solution of these problems. 



(5) The determination of the absence or presence of paleontologic 

 data sufficient to differentiate the three primary divisions of the Cam- 

 brian group. 



(6) The detailed geographic distribution of the formations referred 

 to the Cambrian throughout the State. 



Canadian extension. — The Cambrian group on the line of the Cana- 

 dian extension north of Vermont, in the vicinity of Quebec and down 

 the St. Lawrence River, requires detailed study in all its parts, both to 

 determine the stratigraphic succession and character of the beds and 

 the relation of the strata to the subjacent and superjacent series. One 

 of the important problems presented is the determination of the origin 

 of the limestone bowlders in the Point Levis conglomerate that carry 

 the Upper Cambrian fauna, and those of the Sillery shale that carry 

 the, Lower Cambrian or Olenellus fauna. In fact, the entire Cambrian 

 group of this portion of Canada requires full investigation. 



New Jersey. — In New Jersey it is desirable to ascertain : 



(1) The relation of the quartzite that has been referred to the Pots- 

 dam, to the subjacent Green Pond Mountain rocks. 



(2) The representatives in New Jersey of the Pennsylvania Primal 

 slates of Prof. Rogers. 



Pennsylvania. — In the State of Pennsylvania attention should be 

 given : 



(1) To determining, by paleontological evidence, the exact age of the 

 quartzite which has been referred to the Potsdam sandstone by all 

 authors. 



(2) To a careful study of the upper Primal slate, for the purpose of 

 determining the line of demarcation between the Cambrian and Silu- 



