THE MESOPHYTIC ERA. 



407 



As already indicated, the inclusion of the Permian in the Mesophytic runs 

 counter to the accepted geological usage, but the close relationship between 

 it and the Triassic can not be ignored. Moreover, cooled or arid conditions 

 not only characterized the Permian and Triassic, but extended through the 

 Jurassic as well, while both periods agreed in the reduction and disappearance 

 of the Paleophytic types and the evolution of a new gymnospermous flora 

 (Chamberlin and Salisbury, 1906 : 2 : 632, 634 ; 1906 : 3 : 38 ; Schuchert, 1914 : 279) . 



132.0 



149.0 



193.0 



83.0 



198.0 



36.0 

 10.0 



105.0 



135.0 



3'3^= 



®o?=° 



^<^o 



Sandstone 



Slates and shales with glaciated boulders 



Sandstone 



Glacial mudstones with striated boulders 



Sandstone 



. Soft sandstones— small glaciated boulders 

 Chiefly sandstones— some glaciated boulders 



Glacial beds (apparently till). 



Mudstone — some glaciated boulders 

 Soft mudstones— some glaciated (?) 



Conglomerate and sandstone.— Some glaciated 



blocks 

 Hard sandstone— abundant glaciated blocks 

 Sandstone 



Mudstones with glaciated blocks. 



Sandstone— contorted laminae below 

 Glacial sandstone 



Sandstone and conglomerate with some 



f^, . . , . ^ glaciated stones 



(alaciated mudstones 

 Sandstone and conglomerate 



Beds containiTig glacial boulders 

 Lower Silurian slate and quaftzfte. 



Fig. 43.— Section showing position and relations of Permian 

 glacial beds in Australia. After David. 



The profound deformation of the Permian extended well into the Triassic 

 and was followed by an invasion of the sea, which began in the closing staees 

 of the Triassic and continued into the Jurassic. The interior of the continent 

 remauied land throughout the Triassic and Jurassic, and appears to have been 

 marked by extensive arid climates. Pronounced orogenic movements occurred 

 at the close of the Jurassic, finding expression chiefly in the Sierra Nevada 





