200 A. S. PACKARD, Jr., ON THE GLACIAL PHENOMENA 



and whether there is an overlying bed of sand such as the sheets of sand resting every- 

 where on the upper boulder clay. At present there have been revealed no signs of this 

 lower bed of sand clay, and the lowest clay beds we are acquainted with seem to graduate 

 into the rewashed, more inland, and more recent boulder or brickyard clays 



In adopting the term Quaternary Period, we would use it in the amended sense proposed 

 by D Archiac in 1848, in his « Histoire des Progres de la Geologie." From his able re 

 view of all the prune characteristics so trenchantly dividing this Period from the Pliocene 

 Tertiary, we are led with that author to consider this Period as rather equivalent to the 

 Tertiary as a whole, than to either of its three subdivisions; and rather as the beginning 

 of a new Epoch or Period, than the close of the Tertiary. The distinctions, as shown by 

 D Archiac, obtain no less in the tropics than in the high latitudes. In tropical America 

 the period is marked off from the Tertiary by the appearance of the great mammals the 

 Herbivores characterizing the formation in America, and the great Carnivores the deposit 

 of the Eastern hemisphere. About the Mediterranean the Tertiary Period closed with the 

 upheaval of the Sub-Apennines of Italy, or Alps of Valais. 



Professor Dana in his « Manual of Geology," states further important distinctions, such 

 as the rise of land in the high latitudes which had not before taken place since Paleozoic 

 times ushering m the Period of great glaciers, and thus serving, over one half of the sur- 

 face ot the globe, to further separate this epoch from the Tertiary 



Another feature of this Period is the great uniformity of climate over broad, continental 

 areas, and the wide distribution in space of certain species most characteristic of the Qua- 

 ternary Formation. Such are the occurrence, on both hemispheres, of the musk-ox the Si- 

 berian mammoth (& primigemus), and among marine mollusca of Leda arctlca Gray, Sara 

 (portlanchca), which is now restricted to the circumpolar seas.' 



General Conclusions. 



To account for all the facts which have been developed above, we must assume — 



I That the northern portion of North America, that is, the boreal and arctic' regions 



stood at a much higher level above the sea than now. We have given good evidence that 



it stood at least 360 feet above that level in Labrador. It would be safe to assume that 



the coast hue stood at an elevation not falling short of 600 feet. While this increase in the 



i DArchiac in the Resume General of the first part of his clystique generate et de courte duree," seems to be equivalent 



volume on the Quaternary Penod, divides the epoch into five to the Saxicava sands of American authors e( l ulvalent 



periods- for an enumeration of which we would refer the The lacustrine or Terrace Period of American „eoloo-is,s he 



reader to Ins volume But the differences upon which that also includes in this 3d Periode, which is as distinct S the 



earned and philosophic author bases his Periods 3 and 4, seem Saxicava Sands as the latter is from the Leda C ays - he 



to us not well founded. They both together correspond to three being unconformable and accompanied b d,s n t o,l 



our Leda clay of the northeast coast of North America. " Pe- lations of land. "ist.nct °*<-"- 



riode (4), de calme pen prolon<*ee," he characterizes bv the TT;= 1 ,» „ i . , „ . 



uT-it i i •► r a V f „ „ "' ar< "- re ™' ses °y lue Wis 1st and most recent period of ex st no- -daciers in the 



"Till and deposits ot Arctic shells;" while Periode (3), a AIns and " nrohablv ntl,». /t ■ e ■ T, . , 



later one, is characterized by the « Pampaan deposits/he by" poHshed s£e f^ZSSTT "^T^ 



development of the fauna of Great Mammals and nlarine, flu- Jr. J, s^Ul^d^ ^ ZcToSs oT he' 



«z£L" ° l rt '^«'^<* 'a*'- «»'«■<*« Alps," being of local origin, seems an artifi^subd^visLn 



n „ t x „ I . ,. „, . , wlien applied to the Quaternary period generallv. 



On the contrary, we find in Maine, in the upper part of the The term Leda Clay, first proposed by Dr. Dawson and 



Leda cay the remains of the bison associated with Leda arc- adopted by the Canadian geologists" characterizes much better 



V ff t D ° W P Urel y, C,r «' m P° lar ' f lle the bison inhabits this formation in northeastern America than the term ChaZ 



iod IT'DArTac IF -T i ^ ^T^ T ** *** **«*> «"*» ^ a shall °" ""»* - » s. gh Z 

 nod 3 ot D Archiac. IPs Periode (2), de transport cata- tent, where the strata are but partially developed, and some 



of the most characteristic fossils entirely wanting. 



