EVIDENCE OF THE FOSSIL FLOKA. 191 



editions of " Cook's Yoyages," there are several notes along 

 the tract of the great navigator that indicate where, in mid 

 ocean, trees, or fragments of trees, had been picked up. These 

 entries, however, are but few, though they belong to all the 

 three voyages together : if I remember aright, there are only 

 five entries in all, — two in the Northern and three in the 

 Southern Pacific. The floating shrub or tree, at a great dis- 

 tance from land, is of rare occurrence in even the present 

 scene of things, though the breadth of land be great, and 

 trees numerous ; and in the times of the Silurian and Old 

 Red Sandstone systems, when the breadth of land was ap- 

 parently not great, and trees and shrubs, in consequence, not 

 numerous, it must have been of rarer occurrence still. We 

 learn, however, from Sir Charles Lyell, that in the " Hamil- 

 ton group of the United States, — a series of beds that cor- 

 responds in many of its fossils with the Ludlow rocks of 

 England, — plants allied to the Lepidodendra of the Carboni- 

 ferous type are abundant ; and that in the Lower Devonian 

 strata of New York the same plants occur associated with 

 ferns." And I am able to demonstrate, from an interesting 

 fossil at present before me, that there existed in the period 

 of the Lower Old Red Sandstone vegetable forms of a class 

 greatly higher than either Lepidodendra or ferns. 



In my little work on the Old Red Sandstone, I have re^ 

 ferred to an apparent lignite of the Old Red of Cromarty, 

 which presented, when viewed by the microscope, marks of 

 the internal fibre. The surface, when under the glass, re- 

 sembled, I said, a bundle of horse-hairs lying stretched in 

 parallel lines : and in this specimen alone, it was added, had 

 I found aught in the Old Red Sandstone approaching to proof 

 of the existence of dry land. About four years ago I had 

 this lignite put stringently to the question by Mr Sanderson ; 

 and deeply interesting was the result. I must first mention, 

 however, that there cannot rest the shadow of a doubt re- 



