422 Nezv York State Museum 



shales, limestones and a few beds of coal, with a thickness 

 of 1000 feet. In the Maritime Provinces of Canada red 

 shales and sandstones indicate inclosed basin conditions 

 at this time. Through the west and the southwest the 

 shallow seas of the early part of the period withdrew in 

 the latter part leaving salt lakes in which deposition of 

 salt and gypsum took place, which together with the sun- 

 cracked and ripple-marked red beds indicate an arid cli- 

 mate. There is evidence of widespread glaciation in the 

 Permian, probably greater than that of our "Great Ice 

 Age." Permian glacial deposits have been found in 

 India, South Africa, Australia, Germany, England, 

 Brazil, Argentina and possibly Massachusetts in North 

 America. The close of the Paleozoic is marked by moun- 

 tain-making disturbances of almost worldwide occur- 

 rence, beginning with late Mississippian. This disturb- 

 ance reached its culmination at the end of the Permian 

 when the deposits of the Appalachian geosyncline were 

 elevated into the Appalachian mountains. The folding 

 extended in a northeast-southwest direction from Nova 

 Scotia southward into Alabama and the Ouachita moun- 

 tains of Arkansas. 



Life. Mississippian life was diversified. The great 

 variety and richness of the crinoids is noteworthy, and 

 great thicknesses of limestone were built up from their 

 remains. Blast oids (Pentremites) reach their culmina- 

 tion here and are the guide fossils to the marine deposits. 

 In these rocks also are found the characteristic echinoid 

 (Melonechinus) and a peculiar bryozoan' (Archimedes) 

 with a screwlike axis. Brachiopods are abundant, the 

 genus Productus being characteristic of all three Carboni- 

 ferous periods. Bryozoans and cup corals are also 



