Frazer.] OjZ [Dec. 4, 



the dawn of life); "Matinal" (or the morning. Same metaphor); 

 "Surgent" (or rising), &c., to the lower divisions of the Palaeozoic ; and 

 "Cadent" (or falling) ; " Umbral" (or darkening) ; "Vespertine" (or 

 evening), &c., to the later divisions of the Palaeozoic, the insurmountable 

 objection is made that they do not describe any general state of facts. 

 Thus it might be asked : Of what are these rocks the beginning, dawn, 

 evening? Evidently of the second only of the four arbitrary and artificial 

 divisions by age which geologists have constructed for their temporary 

 convenience. The plan adopted by the New York geologists of giving a 

 name to each formation, which should either recall the locality where it 

 was characteristically displayed, such as the "Potsdam sandstone ;" or 

 describe it lithologically, as the "Calciferous sandrock," the " Mar- 

 cellus shales," the "Oneida conglomerate," &c, would be a good 

 one for provisional use, were it not that in addition to the geographical 

 designation, a lithological definition is added, which, because restricted 

 in the area to which it is applicable, is as often inaccurate as the time de- 

 scription of Rogers. Thus the " Potsdam sandstone " is a "Hellain Town- 

 ship quartzite, " in York county, and Prof. Fontaine, of Virginia, thinks it 

 represented by a peculiar schist containing quartz fragments in Virginia ; 

 and some persons are sure that it occurs in other places as a gneiss. The 

 "Calciferous sandrock " of New York is the same formation which makes 

 up the major part of the broad and fertile limestone valleys of Lancaster, 

 York, Cumberland and Franklin counties, &c, where it is not a sandrock 

 at all. 



As there are various objections to every system yet proposed, I have 

 adopted here that recommended by the International Congress of Geolo- 

 gists at its Berlin session. 



The Archaean (or beginning) in this classification comprises those rocks, 

 usually crystalline in structure, but of very varied and divergent charac- 

 ter, in or below which the very earliest known forms of life occur — and 

 those very sparingly — in York county. This series comprises all the rocks 

 which are geologically inferior to the Hellam Township quartzite. 



The Palmozoic (or " old life ") includes all the rocks from and including 

 the Hellam quartzite to the New Red sandstone, and is made up of the 

 quartzite, hydro-mica schists, and their included iron ores, the great blue 

 and buff limestone on which the city of York is built, together with that 

 of Lower Windsor township ; that near New Holland, in Manchester 

 township ; around Newmarket in northern Fairfax township ; and north 

 of Dillsburg in northern Carroll township. 



The Mesozoic (or "middle life ") rocks are the reddish-brown sandstones 

 and shales (and perhaps the igneous rocks penetrating them) which cover 

 almost the entire northwestern part of the county. If the fancy 

 might be indulged of likening the outline of the county to that of the 

 lower part of a horse's leg, this formation would constitute the fetlock 

 joint and all that portion immediately above the hoof proper. 



The Gainozoic (or "new life") includes all those rocks of which the 



