RECORDS OF MEETINGS OF 1908 475 



Summary of Papers. 



Professor Perkins said in abstract: So far as satisfactorily determined, 

 the Cambrian of Vermont occupies a narrow strip from north to south 

 through the State between the Green Mountains and Lake Champlain. 

 In some places the beds reach the shore of that lake and form the boldest of 

 the headlands. 



Northward the Cambrian extends to the Gulf of St. Lawrence and south 

 through New York to middle Alabama. 



It is probable that there are derivatives from Cambrian strata in and 

 east of the Green INIountains, but none have been certainlv identified. So 

 far as studied, all the beds belong to the Olenellus zone of Walcott, or 

 Lower Cambrian. By a very interesting and extensive fault and overthrust 

 Cambrian strata were lifted and thrown over the Utica. In all there are 

 not less than 10,000 feet of Cambrian beds in western Vermont. These 

 beds consist of 1,000 feet of more or less silicious limestone, and the other 

 rocks are shales, sandstones, quartzites, conglomerates, of very diverse 

 color, composition and texture. In a few places the red sandrock beds 

 change to a thick, bedded, brecciated, calcareous rock, which, when worked, 

 is the Winooski or Champlain marble, — a mottled red and white stone used 

 in many large buildings all over the country. 



Few of the beds are fossiliferous, but some abound in trilobites, Olen- 

 ellus, Ptychoparia, etc., and a few brachiopods, worm burrows, trilobite 

 and other tracks, etc., are also found. In all, the number of species is not 

 large, and probably not more than fifty have been found. Of these, trilobites 

 form the larger number, brachiopods coming next. 



Most of the beds are thin, but some have a thickness of several feet. 

 A large portion of the species from the Vermont beds were described, many 

 of these not having been found elsewhere. 



The great beds of roofing slate which are extensively worked in south- 

 western Vermont are included in the Cambrian, 



Remarks with reference to this subject were made by Professors Hitch- 

 cock, Grabau and Kemp. 



Professor Kemp showed a series of cross-sections illustrating in detail 

 the structural features of the deposits discussed in his paper. 



Professor Wherry said in abstract: The Newark series in eastern Penn- 

 sylvania is divisible into five formations and attains a total thickness of over 

 20,000 feet. In the upper part there is a large trap sheet, about 1,500 feet 

 thick, which shows the character of an intrusive sill. 



Copper was first mined in this region at Bowman Hill, on the Delaware, 

 by the Dutch from New Amsterdam, about 1650; but the most important 



