TRIASSIC SYSTEM. 79 



of which contains coal-beds. Very valuable beds of coal and beds of good argil- 

 laceous iron ore are distributed through it. Many fossils have been described from 

 these rocks, and among them Dromatfierium sylvestre, the earliest fossil mammal yet 

 discovered in America. The rocks occur in Nova Scotia, on the north and south 

 sides of Cobequid Bay, from Moose River to the mouth of North River, and on the 

 south side of the Bay of Fundy. Prince Edward's Island, which stretches for 125 

 miles along the northern coast of Nova Scotia and New Brunswick, consists of 

 rocks of this age. . 



§ 172. The red beds of the Triassic, consisting of every texture of sandstone 

 and all varieties of red, are distributed almost throughout the Rocky Mountain 

 system from Mexico to the Arctic regions, covering hundreds of thousands of 

 square miles. Fossils have been collected and described from every territory and 

 from nearly every mountain range throughout this vast extent of country. Over 

 extensive areas of country the Triassic rocks are more thau a mile in thickness, 

 and bear internal evidence of having been deposited in the depths of the ocean 

 without any mechanical sediment. Not a single species of any organism found in 

 rocks earlier or later than the Triassic have ever been found within it, and very , 

 few genera are common to it and rocks of earlier or more recent date. 



§ 173. In Colorado and Utah the lower part of the Triassic has been called 

 the Shinarump Group, and the upper part the Vermilion Cliff Group. The rocks 

 of the Shinarump are persistent in their characters for hundreds of miles, and the 

 coloring is strong and deep. They weather into striking architectural forms and 

 terraced buttes. The rocks of the Vermilion Cliff Group are colored a brilliant 

 red, approximating vermilion, or sometimes inclining to orange, and constitute the 

 great cliff-forming series of the West. The Group consists of massive layers of 

 homogeneous sandstone, from 100 to 300 feet in thickness, with shaly layers inter- 

 vening ; the shales disintegrate, and thereby the sandrock is undermined and breaks 

 off vertically. This process, in time, has presented a series of perpendicular walls 

 and sloping taluses. In the West Humboldt Range of Mountains the lower part has 

 been called the Koipato Group, and the upper part the Star Peak Group. The maxi- 

 mum thickness in this region has been estimated at 16,000 feet. The fantastic 

 columns in the "Garden of the Gods" and in Pleasant Park, Colorado, have been 

 weathered out of the sandstones of this System. 



