126 THE CAMBRIAN. Tbull.81. 



Geographical distribution. — In its geographical distribution this primal series ranges 

 coextonsively, or nearly so, with the other formations of the older Paleozoic division 

 to be presently traced; that is to say, it shows two great continuous outcrops, one 

 stretching southwest along the Appalachian chain and the other west from the St. 

 Lawrence, through New York, Canada West, Northern Michigan, Wisconsin, and 

 Minnesota beyond the Mississippi. It is probably likewise brought to the day in 

 theanticlinals of Missouri, Arkansas and Texas, which elevate the gueissic strata on 

 which it rests. 



The only fossils found were a peculiar fucoid in the newer Primal 

 slate, annelid borings in the Primal white sandstone, u one or two 

 brachiopodus mollusks, especially lingula. In Wisconsin and other 

 northwestern localities this formation contains several species of tri- 

 lobites, and abounds in lingular obolus, and an orbicula." l Triiobites 

 were also found on Lake Champlain. 



Under the heading of " Equivalents v is the following: 



These strata seem to be on the horizon of the lower Festiniog group or liugula 

 flags of England, and equivalent to the obolus and liugula sandstone of Sweden anc 

 Russia. They represent, too, the primordial zone of Bohemia, and are therefore 01 

 the horizon of the very dawn of discovered life. 2 



This summary of Prof. Rogers gives his information respecting th< 

 Primal series in Pennsylvania, Virginia, and Tennessee up to the time oi 

 publication. Under the heading of " Depositions and disturbances oi 

 the Primal period/' he discusses the probable conditions under which 

 the sediments were deposited, and sums up the period as one of vast 

 duration ; " an enormous age of quiet sedimentation with almost n< 

 life in the wide turbid sea." 3 The paleontological record for the Primal 

 series is given a very few words : Three or four fossils known in th< 

 white sandstone, and a vaguely defined plant in the subjacent shah 

 in the Appalachian region. But in Wisconsin, the white sandstom 

 imbeds, on a succession of thin doors, some seventeen more species. 

 Two of these are identical with those of the eastern outcrop, so th< 

 total u umber of species known at that date was eighteen. The distribu- 

 tion of the Primal series in Pennsylvania is tabulated in volume I 4 am 

 local details are given in the description of the various counties in whicl 

 outcrops of the rocks and slates occur. 



On an accompanying geological map the geographic distribution ol 

 the Primal series is delineated. As a whole it extends with many in- 

 terruptions diagonally across the southeastern portion of the State, 

 from South Mountain in Adams County to Northampton and Bucks 

 Counties, on the Delaware River. 



Two maps of sections also accompany the report of 1858. On tin 

 line of section No. 2, the Primal is represented, in Northampton County, 

 at Frey's Run and along Durham Creek to the Delaware River. At 

 Attleborough, in Bucks County, a synclinal of the Primal sandstone 

 is represented as occurring in the midst of the older Primal slate. 



•Op. cit., p. 751. 2 Op. cit, p. 752. 3 0p. cit., p. 781. 4 Op. cit., pp. 122, 123. 



