MATTHEW] GEOLOGICAL AGE OF THE LITTLE RIVER GROUP 73 



he would state the causes which appear to him to have determined the 

 Carboniferous aspect of the contained flora. 



It is quite natural that those who are guided in the determination 

 of the age by the aspect of the flora should think that the plants are Car- 

 boniferous, for it should be remarked that only one aspect of the De- 

 vonian Flora is known in Europe, viz : that grouping of plants which 

 grew under an arid and cold climate, or one where a short season of 

 rapid growth alternated with a long period of drought within the year. 

 Both in Europe 'and Eastern North America such conditions prevailed 

 through much of Devonian time, and were accompanied by the deposition 

 mostly of red sediments. Occasionally where plant remains were un- 

 usually abundant the associated layers took on a gray hue. 



This red colour would seen to be accounted for in the following way. 

 There had been a lengthened period of Silurian time when considerable 

 areas of the earth's surface in eastern North America and Northern 

 Europe had been above the sea; and in some areas even in later Ordo- 

 vician time there had been such an emergence. At the time a warm, tem- 

 perate and even subtropical climate prevailed, leading to the softening 

 and oxidation of the strata to great depths. Limestones of the late Or- 

 dovician and the Silurian time are found north of Labrador and up into 

 the ArcticI islands. As these limestones contained abundant corals, etc., 

 it may be inferred that they were deposited in the tepid waters where 

 such organisms could flourish. If this were the case so far to the north, 

 the temperature in Labrador must have been moderate, and in the Mari- 

 time provinces of Canada and the eastern borders of the United States 

 even subtropical: the Devonian red sediments then could have been 

 formed of the decomposed rocks of the Silurian uplands, forming soils 

 that were swept rapidly into the sea by ice or rivers during the Devonian 

 period. Their colour is an evidence of profound oxidation of the up- 

 lands during the preceding warm Age. 



The strata of the Little Eiver group do not show much evidence of 

 this oxidation of the upland soils because they were accumulated in a 

 delta covered by a luxuriant vegetation, hence the red colour was mostly 

 discharged and the terrane closely resembles the Coal-measures in the 

 appearance of the beds and of the contained plants. But when the flora 

 is investigated in detail, important differences are found to have existed 

 between this flora and that of the Carboniferous Time and the resem- 

 blance is rather superficial than intrinsic, as may be gathered from the 

 following article on the plant remains. 



To the writer, therefore, it appears that the Carboniferous aspect of 

 the flora of the Little Eiver group is due chiefly to its deltaic origin, and 

 in a less degree to the prevalence of a mild and moist climate during the 

 time when it flourished. 



