CHAP. III. UPHEAVAL OF THE SHORES OF THE FIRTH OP FORTH. 49 



galley ; its stern, formed of a triangular-shaped piece of oak, 

 fitted in exactly like those of ovir day. The planks were 

 fastened to the ribs, partly by singularly shaped oaken pins, 

 and partly by what must have been square nails of some 

 kind of metal; these had entirely disappeared, but some of 

 the oaken pins remained. This boat had been upset, and 

 was lying keel upjDermost, with the prow pointing straight up 

 the river. In one of the canoes, a beautifully jDolished celt 

 or axe of greenstone was found, in the bottom of another a 

 plug of cork, which, as Mr. Geikie remarks, "could only have 

 come from the latitudes of Spain, Southern France, or Italy."* 



There can be no doubt that some of these buried vessels 

 are of far more ancient date than others. Those most 

 roughly hewn may be relics of the stone period; those more 

 smoothly cut, of the bronze age; and the regularly built boat 

 of Bankton may perhaps come within the age of iron. The 

 occurrence of all of them in one and the same upraised 

 marine formation by no means implies that they belong 

 to the same era, for in the beds of all great i-ivers and 

 estuaries, there are changes continually in progress brought 

 about by the deposition, removal, and redeposition of gravel, 

 sand, and fine sediment, and by the shifting of the channel 

 of the main currents from year to year, and from century to 

 century. All these it behooves the geologist and antiquaiy 

 to bear in mind, so as to be always on their guard, when 

 they are endeavoring to settle the relative date, whether of 

 objects of art or of organic remains imbedded in any set 

 of alluvial strata. Some judicious observations on this head 

 occur in Mr. Geikie's memoir above cited, which are so much 

 in point that I shall give them in full, and in his own words. 



" The relative position in the silt, from which the canoes 

 were exhumed, could help us little in any attempt to ascer- 



* Geikie, Geol. Quart. Journ., vol. xviii. p. 224. 



