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, 

 west of the eastern Archaean ranges, the Triassic enters largely into 

 the constitution of various mountain ridges, as those of the Elk, 

 Wahsatch, and Uintah ranges. It has great thickness, and is fossil- 

 iferous, in Western Nevada. It constitutes 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 on 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 

 line> 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 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, and the Susquehanna at Bainbridge, and ends in Orange County, Va. An 

 area, farther south, in Buckingham County, ma) 7 be part of it. 



5 to 8. Shorter areas in Virginia, more to the eastward, and 9, more to the westward. 

 No. 5 lies fifteen miles west of Richmond. No. 6 commences in the same line at Fred- 

 ericksburg, and extends nearly to Baltimore. No. 7 extends from Chesterfield through 

 Richmond to Petersburg, and appears again in Sussex County. No. 8 is in Prince 

 Edward County. No. 9 extends through Pittsylvania County to Dan River. 



9 and 30. Two North Carolina areas. — One (No. 10) begins six miles south of Ox- 

 ford, in Granville County, passes to the westward of Raleigh, crosses Deep River, where 

 it contains coal, and extends six miles into South Carolina : width six to eighteen miles. 

 The second (No. 9) is that of Dan River, and is properly a continuation of the most 

 western Virginia area; it contains the Dan River coal region. The beds of the former 

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



