MESOZOIC ERA. AGE OF REPTILES. 341 



rassic marsupial, and also a living marsupial most nearly 

 allied to them. 



SECTION III. JURA-TRIAS IN AMERICA. 



Areas ; Atlantic Border. All along the eastern slope 

 of the Appalachian chain, from Nova Scotia to South Caro- 

 lina, in the Archaean region of the map on page 272, are 

 found elongated patches of sandstones and shales which 

 belong to this period. One of these is in Nova Scotia 

 and Prince Edward Island ; the next, going south, is the 

 celebrated Connecticut River Valley sandstone ; the next 

 a long, narrow patch commencing in New York, passing 

 through New Jersey, Pennsylvania, Maryland, and ending 

 in northern Virginia ; then two or three patches in eastern 

 Virginia, about Richmond and Piedmont ; and, lastly, 

 some on the Deep River and the Dan River of North 

 Carolina. They all lie in hollows unconformably on the 

 Archaean gneiss, and therefore their age can not be known 

 except by fossils ; but these, though few, seem to indicate 

 that they represent the whole Jura-Trias, although most 

 writers speak of them as Triassic. In all these patches 

 are found remarkable outbursts of igneous rocks, often 

 columnar in structure, which by erosion have formed the 

 so-called trap-ridges. Such are Mounts Tom and Holy- 

 oke, in the Connecticut Valley patch, and the Palisades 

 of the Hudson River in the New Jersey patch. 



Interior Kegion. Red sandstones, poor in fossils, 

 but probably referable to this period, are found in many 

 places in the Plateau and Basin regions: 



Pacific Slope. On both sides of the Sierra, rocks of 

 this age, in a metamorphic condition, form the auriferous 

 slates of this region. 



Life- System. 



Life, no doubt, abounded, but the conditions were 

 unfavorable for preservation. We can, therefore, take 



