ON CHANGES IN THE DISPOSITION 9-> mi mi ritime forests, extends the well-known marshy tracts by which so many of these shores are skirted; often co vering, as in Borneo, spaces almost incredible, and with effects but too well known. The last geographical effect of this nature which I need notice, is the formation of fresh water lakes on the margin of the sea; being an occasional result of that process which fills a bay by the production of a spit or bar. The descent of the terrestrial alluvia being checked by the tide, a bank is produced, which gradually raising itself above the waters, becomes dry land; continu ing to receive accessions of materials on the interior side, and often on both. If the entrance of a powerful river, united to a peculiar form in the shore, determines a rapid increase of the land at the aperture, its channel may at length become so narrowed and prolonged through the bar, that the further entrance of the sea is checked; and thus a fresh water lake is the result. This occurs in the Crimea, according to Pallas, and in the Gulf of Mexico ; while, in our own island, the whole process can be seen, from the commencement to the termination, in different places. The long trans verse spits of the Gare loch and Loch Fyne are exam ples of the first stage : at the Connel ferry and Balahu- lish, these spits have become plains ; leaving, at the latter place in particular, but a narrow passage for the Avater: Avhile, whether the ultimate result will ever happen in these places or not, it has taken place in a small lake near Cape Rath, now occupying what w r as once a salt bay. Of antient unknown Currents Whatever imagined facility may be afforded by such currents in explaining geological phenomena, it is an hypothesis which has been rendered repugnant by its