38 GEOLOGY OF THE ISTARRAGANSETT BASIIST, 



height above the coast Hue, and most Hkely at some distance inland from it. 

 These considerations serve to support the hypothesis, which is suggested by 

 many other features of the Atlantic shore line of North America, that the 

 shore line in later Paleozoic time lay farther east than it does at present. 



ORIGINAI. BISTRIBTJTIOK OF THE EAST AFFAI.ACHIAN COAI. FIELD. 



The distribution of the Carboniferous strata with reference to the main 

 axis of the Appalachian system affords some valuable information as to the 

 movements and attitudes of the continent during the later stages of Paleo- 

 zoic and the earlier stages of Mesozoic time. It is noteworthy that, while 

 the Carboniferous of the West Appalachians extends to the southward 

 until the beds pass beneath the Cretaceous and Tertiary deposits which lie 

 to- the noi-th of the Grulf of Mexico, rocks of that age are wanting along the 

 Atlantic coast until we attain the latitude of northern Connecticut and 

 southern Massachusetts. Thence to northern Newfoundland accumulations 

 of this age occur, though in detached basins which were evidently formed 

 as somewhat separate areas. The uniform absence of Carboniferous deposits, 

 and indeed of the Paleozoic beds above the Silurian horizon, along the 

 southern portion of the Atlantic coast line of the United States, clearly indi- 

 cates the long continuance of this pai-t of the continent in the emerged state, 

 a state which appears to have continued in the southern section to Triassic 

 time, and perhaps to the Newark division of that age. If Coal Measures 

 strata had been deposited on this part of the Atlantic coast above the pres- 

 ent sea level, it is hardly to be believed that considerable remnants would 

 not have remained in the Dan River, Richmond, and other basins. The 

 natural conclusion is that these beds were not laid down, but that the shore 

 from the Hudson southward remained in the elevated state, and that in this 

 field Carboniferous strata were not accumulated, while farther north the 

 conditions so favored this work of deposition within the region about the 

 mouth of the St Lawrence that the sections of this stratigraphical division 

 are on the average thicker than they are in the West Appalachian field. 



With the advent of the Triassic epoch the whole coast line appears to 

 have been lowered, so that the beds of this age probably formed a more or 

 less continuous sheet from South Carolina to Nova Scotia. 



In the Carboniferous downsinking of the eastern shore the conditions 

 which brought about the formation of the Coal Measures do not seem to 

 have extended as far south as the valley of the Connecticut. The pre- 



