| New York | Gaspé | Southern | Coast Subdivisions. | and | and Bay des | New | of | Western Canada.| Chaleurs. | Brunswick. | Maine. --------------+----------------+--------------+--------------+----------- Upper | Chemung | Upper |Mispec Group. | Perry Devonian or | Group. | Sandstones. | Shale, |Sandstones. Erian. | |Long Cove, &c.| Sandstone, | | | Scauminac | and | | | Beds. |Conglomerate. | | | | | Middle | Hamilton | Middle | Little R. | Devonian or | Group. | Sandstones. | Group | Erian. | | Bois Brulé, | (including | | | Cape Oiseau, | Cordaite | | | &c. | Shales and | | | | Dadoxylon | | | | Sandstone).| | | | | Lower | Corniferous | Lower | Lower | Devonian or | and | Sandstones. |Conglomerates,| Erian. | Oriskany | Gaspé Basin, | &c. | | groups. | Little Gaspé,| | | | &c. | | | | Campbellton | | | | Beds. | | --------------+----------------+--------------+--------------+-----------
It may be proper, before closing this note, to state the reasons which have induced me to suggest in the following pages the use of the term "Erian," as equivalent to "Devonian," for the great system of formations intervening between the Upper Silurian and the Lower Carboniferous in America. I have been induced to adopt this course by the following considerations: 1. The great area of undisturbed and unaltered rocks of this age, including a thickness in some places of eighteen thousand feet, and extending from east to west through the Northern States of the Union and western Canada for nearly seven hundred miles, while it spreads from north to south from the northern part of Michigan far into the Middle States, is undoubtedly the most important Devonian area now known to geologists. 2. This area has been taken by all American geologists as their typical Devonian region. It is rich in fossils, and these have been thoroughly studied and admirably illustrated by the New York and Canadian Surveys. 3. The rocks of this area surround the basin of Lake Erie, and were named, in the original reports of the New York Survey, the "_Erie Division_" 4. Great difficulties have been experienced in the classification of the European Devonian, and the uncertainties thus arising have tended to throw doubt on the results obtained in America in circumstances in which such difficulties do not occur.