TRIASSIC PERIOD. 405 



Markings on the rocks. — In many regions, the layers of rock are 

 covered with ripple-marks and raindrop-impressions or mud-cracks, — 

 evidences in part of exposure above the water, during the progress of 

 the beds. 



In the Connecticut valley, and to a less extent in New Jersey and 

 Pennsylvania, the surfaces of the beds are sometimes marked with the 

 footprints of various animals, as insects, reptiles, and birds ; and over 

 12,000 tracks, averaging 100 tracks for each species of animal, have 

 been taken out. 



2. On the Gulf Border, there are no Triassic rocks, excepting such 

 as may possibly be buried beneath later formations. 



3. The formation supposed to be Triassic, between the Mississippi 

 and the summit of the Rocky Mountains, consists of sandstones and 

 marly tes of usually a brick-red color, and often contains gypsum. It 

 covers a large area between the meridians of 90° and 102° W., in- 

 cluding the Indian Territory, parts of Kansas and Northern Texas, 

 and a portion of New Mexico. It outcrops at the base of the eastern 

 ridges of the Rocky Mountains. Over the Rocky Mountain region, 

 between the eastern Archaean ranges and the Sierra Nevada, the 

 Triassic enters largely into the constitution of various mountain ridges, 

 as those of the Elk, Wahsatch, Uintah, and Humboldt ranges. It con- 

 stitutes a considerable part of the auriferous slates of the Sierra 

 Nevada, affording fossils in some places. It spreads over much of the 

 Colorado valley, and occurs also near the coast in British Columbia 

 and Alaska. • 



(a.) Areas ox the Atlantic Border. — 1. The Acadian areas. — (1.) A region 

 in Nova Scotia, forming the east side of the Bay of Fundy, and northeastward in this 

 linej along the northern border of the Basin of Mines. (2.) Prince Edward's Island, 

 covering nearly all of it. 



2. The Connecticut River area. 



3. The Southbury area. — A small parallel region in Connecticut, more to the west- 

 ward, in the towns of Southbury and 1 Woodbury. 



4. The Palisade area. — This, the longest continuous line, extends from Rockland on 

 the Hudson River, through New Jersey, Pennsylvania, and Virginia, east of the Blue 

 Ridge, being thirty miles wide in some places in New Jersey, twelve on the Susque- 

 hanna, and six to eight on the Potomac. It crosses the Delaware between Trenton and 

 Kintnerville, the Susquehanna at Bainbridge, and the Schuylkill twelve miles below 

 Reading. 



5 and 6. Short areas in Virginia, parallel to the last, and more to the eastward. The 

 easternmost, or Richmond area, commences on the Potomac, a few miles below Wash- 

 ington, and continues to Richmond and twenty-five or thirty miles beyond. The other 

 lies twenty-five miles west of the Richmond range. 



7 and 8. Two North Carolina areas. — One begins six miles south of Oxford, in 

 Granville County, and follows nearly the line of the Richmond range (of Virginia), 

 crossing Orange and Chatham counties, westward of Raleigh, passing Deep River, 

 where it contains coal, and extending six miles into South Carolina: width six to 

 eighteen miles. A second, between Leaksville and Germantown, Rockingham County, 

 is thirty miles long; it contains the Dan River coal region. The beds of the former have 

 a dip to the southeastward, of the latter, northwestward. 



