294 PROF. E. HULL^ LL.D., ETC., ON THE SUB-OCEANIC 



examined by the members of the Victoria Institute, to see 

 whether they can bear sci-utiny, for I consider that they all relate 

 to the subject of the paper. 



G liar act eristics of the Tipper Tertiary coast-line of Western Europe. — 

 It is essential to place before one the sheets of the Topographical 

 Atlas of France and the large scale charts of the Atlantic sea- 

 board, including the latter relating to the coast southward to Cape 

 St. Vincent ; also the best maps of the north of Spain and the 

 west of Portugal. By the aid of such documents we find that the 

 tract of ocean lying within the bathometrical curve of 200 fathoms 

 pretty well indicates the probable former existence of mere hills, 

 which, previous to their denudation, appear to have been analogous 

 to those still emerged, and like them, of Tertiary origin, along the 

 west coast of France. Within the whole area of the Continental 

 Platform the west coast of France is fringed by a gently sloping 

 sea-bed to the very upper margin of the Grand Declivity. The 

 prolonged action of the currents and waves has here planed away 

 all the pre-existing eminences, filling up all the valleys, with the 

 exception of some traces of those of the principal rivers. 



Along the Spanish coast the bathometrical curve of 200 fathoms 

 in the Bay of Biscay, precisely as we might have anticipated, 

 approaches very near to the shore, skirting, as it does, the 

 Cantabrian mountains. The important gaps and indents in the 

 direction of the old coast-line are exactly what are met with in 

 steep mountainous regions, whose base is washed by the sea, and 

 the flanks of which are furrowed by short impetuous torrents. 



At the period of greatest emersion the Cantabrian mountains 

 must have been a most important chain, and from the fact of their 

 being but a prolongation of the Pyrenees, and lying in the same 

 axis with them, we might be authorised to consider them as having 

 all belonged to the Pyrenees. 



Professor Hull, having described the great European Continen- 

 tal Declivity, all along the eastern shores of the Atlantic, from 

 Rockall to Cape St. Vincent, and summarised the researches of 

 American geologists, who have shown the existence of two escarp- 

 ments along the western shores of the North Atlantic, from the 

 Gulf of Mexico northwards, all along the sea-board of the United 

 States, it seems quite permissible to infer that the tvJiole bed of the 

 ocean included between those shores must have participated in like 

 manner in the subsidence. In those days the greatest depth of 

 the North Atlantic Ocean must rarely have exceeded 2,000 

 fathoms. 



