30 MR. LYELL ON THE PROOFS OF A GRADUAL RISING OF 



subtt-uncata, very abundant ; Tellina solidula ; Donax trunculus ? Dillwyn ; Cyjrrina 

 Islandica, Fenus gallina, Cardium edule, Littorina littorea, Turritella terehra, RosteU 

 lana pes pelicani, and Buccmum reticulatum. This part of the estuary is now always 

 filled with fresh water, except on rare occasions, and for a short time, when a strong 

 wind drives the sea up the river, and causes the water to rise six feet, in which case it 

 becomes brackish. At different heights above the sea, in the valley of the Gotha Elf, 

 between Gothenburg and Trolhattan, marine shells have been found similar to those 

 of Uddevalla. 



Some persons who have been long resident in Gothenburg pointed out to me, as a 

 proof that the water was falling there, that the rocks several feet above the highest 

 water-mark were bare and uncoloured, by which they meant that no lichens grew 

 upon them. 



A similar remark had been made to me at Tjufkil, Svansund, and other places on 

 this coast. It seems probable that some species of lichen may require a much longer 

 time to establish themselves on newly exposed rocks than others ; and I could ob- 

 serve distinctly, near Gothenburg, that some kinds approached nearer the water's 

 edge than others, and that the variety of species became greater and the colour difr 

 ferent on ascending to greater heights. It would therefore be an interesting point for 

 a geologist sufficiently skilled in botany to determine whether the extent of the lichens 

 and mosses downwards towards the water on this coast, where the rocks are supposed 

 to be always rising, presents different phenomena from the line of vegetation on other 

 coasts, where the relative level of the land and sea is known to have remained sta- 

 tionary. 



On many parts of the eastern coast, above described, the sea freezes in severe 

 winters in the Skar ; that is to say, among the rocks and islets which skirt the main 

 land, and where there is almost always still water. As I have before mentioned the 

 accounts which I received of the transporting power of ice in the Gulf of Bothnia, 

 it may be well to state some facts bearing on the same subject which I learnt at 

 Gothenburg. In the harbour of that port there are a great number of strong wooden 

 piles, called dolphins, three or four feet in circumference, the lower parts of which 

 are sunk to a considerable depth in the mud, and firmly fixed in it, so that vessels 

 may be moored to their tops. As these dolphins are annually frozen in, it is found 

 necessary to break the ice round them ; but sometimes this has been neglected, and 

 Mr. Harrison, the English Vice-Consul, informed me, that on such occasions he has 

 known a great number of the piles drawn up together out of the mud six feet per- 

 pendicular, a rise of the river having caused the ice to float up to that amount. 



Mr. Westbeck of Marstrand, to whom I have already alluded, mentioned to me, 

 that having been formerly employed in the Swedish Diving Company for thirty years, 

 he had opportunities of witnessing the extraordinary power of ice to lift up from the 

 bottom of the sea and remove to a distance very heavy masses. In two instances the 

 ice collected round sunken vessels which were under his charge, and having frozen 



