143 



This latter plane or limit, marking the transition from the non- 

 fossiliferous or azoic deposits to those containing organic remains, 

 lies within the middle of the primal series or group, of the Penn- 

 sylvania Survey, that is to say, in the Primal White Sandstone, 

 Avhich even where very vitreous, and abounding in crystalline 

 mineral segregations, contains its distinctive fossiL the ScolitJais 

 linearis. The primal slates beneath the sandstone, and in im- 

 mediate alternation with it, possess not a vestige of organic life, 

 nor has any such been yet discovered anywhere within the limits 

 of the Atlantic slope, or on the northern or western borders of 

 the great Appalachian basin of North America, either in this 

 lower primal slate, or in the other semi-metamorphic grits and 

 schists physically conformable with it, and into which the true 

 Paleozoic sequence of our formations physically extends down- 

 ward. We have thus, then, two main horizons, subdividing the 

 more or less metaraorphic strata of the Atlantic slope into three 

 systems or groups ; the one, a physical break or interruption in 

 the original deposition of the masses; the other, a life-limit or 

 plane, denoting the first advent, so far as is yet discovered, of 

 organic beings. As these two planes are not coincident, but 

 include between them a thick group of sedimentary rocks, sepa- 

 rated from the lower physically, from the upper ontologically, 

 w^e are fully authorized, in the existing state of research, to 

 employ a classification, which recognizes a threefold division of 

 all these lower rocks. To the most ancient or lowest group, it is 

 proposed to continue the name of gneiss, preferring, however, to 

 call this division generically the Gneissic Series, em[)loyinr>- 

 sometimes the technical synonyme Hypozoic, proposed by Profes- 

 sor John Phillips, for these lowest of the metainorphic strata. To 

 the great middle group, less crystalline than the gneissic, and yet 

 destitute of fossils, the descriptive terms semi-metamorphic or 

 Azoic are applicable. And to the third uppermost system, or 

 entire succession of the American Appalachian strata from the 

 primal, containing the earliest traces of life, to the latest true 

 coal rocks, or last deposits of the Appalachian sea, it is here pro- 

 posed to affix^ as for many years past, the well-chosen title, con- 

 ferred on corresponding formations in Europe, of the Paleozoic, 

 or ancient life-entombing system or series. Thus we have the 

 Hypozoic rocks, or those underneath any life-bearing strata ; 



