104 TEE GEOLOGICAL HISTORY OF PLANTS. 



structure, in the upper part of the marine Upper Silurian lime- 

 stones,* proves the flora of the Devonian rocks to have had its 

 beginning at least in the previous geological period, and to charac- 

 terise the lower as well as the upper beds of the Devonian series. In 

 this connection I may state that, from their marine fossils, as well 

 as their stratigraphical arrangement, Sir W. E. Logan and Mr. 

 Billings regard the lower portions of the Gaspe sandstones as the 

 equivalents of the Oriskany sandstone of New York. On the other 

 hand, the great thickness of this formation, the absence of Lower 

 Devonian fossils from its upper part, and the resemblance of the 

 upper beds to those of the newer members of the Devonian else- 

 where, render it probable that the Gaspe sandstones, though defi- 

 cient in the calcareous members of the system, seen farther to the 

 westward, represent the whole of the Devonian period. 



The Gaspe sandstones, as their name imports, are predominantly 

 arenaceous, and often coarsely so, the sandstones being frequently 

 composed of large grains and studded with quartz-pebbles. Grey 

 and buff are prevalent colours, but red beds also occur, more espe- 

 cially in the upper portion. There are also interstratified shaly 

 beds, sometimes occurring in groups of considerable thickness, and 

 associated with fine-grained and laminated argillaceous sandstone, 

 the whole having in many places the lithological aspect of the coal- 

 measures. At one place, near the middle of the series, there is a 

 bed of coal from one inch to three inches in thickness, associated 

 with highly bituminous shales abounding in remains of plants, and 

 also containing fragments of crustaceans and fishes (Pterygotus, 

 Ctenacanthus ? &c.). The beds connected with this coal are grey 

 sandstones and grey and dark shales, much resembling those of the 

 ordinary coal formation. The coal is shining and laminated, and 

 both its roof and floor consist of laminated bituminous shale with 

 fragments of Psilophyton. It has no true under-clay, and has been, 

 I believe, a peaty mass of rhizomes of Psilophyton. It occurs near 

 Tar Point, on the south side of Gaspe Bay, a place so named from 

 the occurrence of a thick dyke of trap holding petroleum in its 

 cavities. The coal is of considerable horizontal extent, as in its line 

 of strike a similar bed has been discovered on the Douglas River, 

 about four miles distant. It has not been recognised on the north 



* The marine fossils of these beds have been determined by Mr. 

 Billings. They are Upper Silurian, with an intermixture of Lower Devo- 

 nian in the upper part. Fragments of Nematophyton occur in beds of 

 the same age in the Bay dcs Chaleurs, at Cape Bon Ami. 



