410 THE CAMBRIAN. [bull. 81. 



The correlation by Prof. N". H. Winchell of the " Granular Quartz * 

 and the " Red sandrock" of Vermont with the " Potsdam " sandstone 

 of the Upper Mississippi Valley and the " Primordial v quartzite of the 

 Northwest appears to be based upon the fact that the u Granular 

 Quartz" of Vermont and Massachusetts rests uuconformably upon the 

 Archean, aud that a similar quartzite is superjacent to Archean rocks 

 in the Mississippi Valley. This same principle of correlation appears 

 in his statement that the stratigraphies relations of the " Granular 

 Quartz " and the Potsdam of New York are the same. He says: "In 

 the first place, they are seen to lie uucouformably upon the older gran- 

 ite." ■ 



Messrs. X. H. Winchell and H. V. Winchell correlated the Winooski 

 marble series of Vermont with the Stockbridge limestone or marble 

 belt of the southwestern portions of the State. 2 



This correlation is based upon (a) the assumed'Primordial age of the 

 iron-bearing limestones aud shales of the Penokee Gogebic range of 

 Wisconsin and theMesabi range of Minnesota, aud their assumed strat- 

 igraphic identity with the limestones aud shales of western Vermont, 

 which correspond to the Stockbridge limestones aud irou ores of west- 

 ern New England ; (b) the known Cambrian age of the Winooski marble 

 series. 



Meek. — As paleontologist of the Hayden and other surveys of the 

 interior and western coutinental area, Mr. F. B. Meek's influence upou 

 the correlation of fossiliferous strata was important. His views upou 

 correlation by paleontologic evidence are given in a report on the Pale- 

 ontology of eastern Nebraska, as follows: 3 



There are probably few well informed geologists who will at the present time 

 maintain that the occurrence of a very similar or even the same group of fossils at 

 widely separated localities necessarily proves the rocks in which they are found to 

 be of exactly contemporaneous origin. The most that is now generally maintained 

 in this regard is that such identity or correspondence of types at very distantly 

 separated parts of the world indicates that the strata in which they are imbedded 

 were formed during the prevalence of identical or similar physical conditions at 

 some time during the same great geological epoch, aud that they hold the same or 

 nearly the same relative position in the geological colurau of their respective districts. 

 For instance, although a stratum in the Rocky Mountains, containing the remains of 

 very nearly the same fauna as some particular suV division of the Devonian system 

 of Europe, might, for aught we know, be hundreds of years older or newer than that 

 particular division, we would have little or no room for doubting that it belonged to 

 the great Devonian series, or possibly even to some definite, known horizon in that 

 series. We could moreover very positively assert in such a case that it would be, 

 according to all past experience, useless to seek there at any lower geological hori- 

 zon for workable beds of coal, or to expect to find Silurian rocks or any of their pe- 



1 The crystalline rocks of Minnesota. General report of progress made in the stndy of their field 

 relations. Statement of problems yet to be solved. Geol. and Nat. Hist. Survey of Minn., 17th Ann. 

 Rep. for 1888, 1889, p. 49. 



* The Taconic Iron Ores of Minnesota and Western New England. Am. Geologist, vol. 6, 1890, pp. 

 263-274. 



3 Report on the Paleontology of eastern Nebraska, in Final Hep. of U. S. GeoL Surv. of Nebraska, 

 Washington, 1872, p. 83. 



