362 PALAEOZOIC TIME CARBONIFEROUS AGE. 



Among the species there was the large coral Lithostrotion basaltiforme, 

 common in both Europe and the United States. One such species 

 is almost sufficient to prove a similar temperature for the ocean 

 over these three distant regions. This Lithostrotion was found by 

 Beechey on the northwest Arctic coast, between Point Barrow and 

 Kotzebue Sound ; and with it occurred other corals, and among the 

 Brachiopods Productus Martini, well known in lower latitudes. The 

 Arctic was, therefore, at that time a reef-growing sea; and if the 

 distribution of corals, forming coral-reefs, was limited by the same 

 temperature then as now, the waters were at no part of the year 

 below '66° F. Besides the above species, there have been identified 

 in the Arctic, the European species Productus sulcatus, Atrypa aspera, 

 A. fallax: these were found on Bathurst and the neighboring 

 islands, in latitudes 75° and 77°. 



The small diversity in the oceanic temperature of the globe is fur- 

 ther shown by the occurrence of the following Carboniferous species 

 in the Bolivian Andes : — Productus semireticulatus, P. longispinus Sow., 

 Aihyris subtilita Hall, and a Bellerophon resembling B. Urii Fleming. 



The coal beds of the Arctic are evidence of a profuse growth of 

 vegetation over an extended area and protracted through a long 

 period. The conditions between the latitudes 70° and 78° were, 

 therefore, analogous to those over the United States from Pennsyl- 

 vania to Alabama and from Illinois to Texas. While a general re- 

 semblance to the ancient flora of the United States and Europe is 

 apparent from the observations which have been made, particular 

 species have not yet been identified. The plants were not mosses 

 of peat swamps, such as now extend far north. If we draw any 

 conclusion from the facts, it must be that the temperature of the 

 Arctic differed but little from that of Europe and America. Through 

 the whole hemisphere — and, we may say, world — there was a genial 

 atmosphere for one uniform type of vegetation, and there were 

 genial waters for Corals and Brachiopods. 



(2.) Moisture of the atmosphere. — A warm state of the globe would 

 necessarily imply a very much larger amount of evaporation than 

 now. The climate would be insular throughout, and heavy mists 

 would rest over the land, making the air and land moist. The 

 comparatively small diversity of climate between the equator and 

 poles would probably be attended with fewer storms than now, 

 and a less rapid movement in the general circulation. 



(3.) Impurity of the atmosphere. — In the present era, the atmosphere 

 consists essentially of oxygen and nitrogen, in the proportion of 

 23 to 77 parts by volume. Along with these constituents there are 

 about 4 parts by volume of carbonic acid in 10,000 parts of air. More 



