Introductory 
of the ocean-bed from the margin of the land to depths of over 1000 fathoms ; just as by means of 
contour lines levelled with the theodolite or spirit-level on the land itself, we are able to present a correct 
picture of the physical features of the emergent areas." 
‘As it was clear that the physical features thus discovered were necessarily the result of meteoric 
agencies carried on over land areas, and involving enormous changes of level of the crust of the globe, 
it was easy to draw the conclusion that by such movements unexpected light would be thrown on various 
problems, such as the distribution of animal and plant life, and the cause of the Glacial Epoch. And I 
asked myself whether, if such great changes of level—of elevation and subsequent depression of the land 
as referred to above—had been determined by the researches of Professor Spencer along the eastern 
borders of the American Continent, similar evidence of oscillation might not be revealed on the opposite 
side of the Atlantic by aid of our Admiralty Charts? 
Greatly stirred by these ideas, I resolved to put them to the test of actual experiment. I therefore 
procured copies of the Admiralty Charts, commencing with those of the British Isles, whose enclosing 
waters are rich in soundings, marked by numbers in fathoms. Taking the 100-fathom contour, which 
in some places nearly represents the edge of the Continental Platform, I traced this isobath southwards 
from Rockall and the Shetland Isles, round by the coast of Scotland and Ireland to the entrance of the 
English Channel. After that I adopted a similar course with lower levels at 250, 500, 750, and 1000 
fathoms, with the result of showing that the channels of the rivers Erne, Shannon, and two others 
completely submerged, which I have named “The Irish Channel River” and “The English Channel 
River,” are continued out through the British and Continental Platform, and descend through lofty walls 
of rock into the abyssal floor of the ocean.? (See Plate II.) 
I need not dwell further on this part of my subject ; suffice it to say that the isobathic contours as 
they were traced along the coasts of France, Spain, and Portugal, along the northern coast of the 
Mediterranean and of the coast of Africa, revealed the hidden wonders of the ancient coast lines, their 
bays, promontories and tremendous precipices; mouths of rivers entering the Pleistocene ocean at 
distances so great from the existing outlets of the same rivers now pouring down their waters from the 
adjoining lands,. that they would be out of sight from the deck of a ship stationed directly over the 
submerged outlets ; Buchivould have been the case with the Congo, the Tagus, and several other rivers 
off the European coast. 
Such are some of the physical features of the submerged landscape of Pleistocene times which will 
be described and illustrated by the maps in the following pages ; nor can they be fully realised unless we 
recollect that the basement floor of the Continental Slope was at that time the actual coast-line of the now 
partly submerged continents at depths tooo to 1200 fathoms from the present surface. 
In the memoir, by Professor Spencer, of my researches along the European coast, in which he 
expresses approval and appreciation, for which I cannot be too grateful, he observes : “These contribu- 
tions are new facts treated in a philosophical manner, and could now perhaps be put in a monographic 
form.” ® It is to be hoped that the distinguished author of the above quotation may be able to carry out 
this proposal as regards his own special region on the western side of the Atlantic.t In publishing this 
monograph I am encouraged to take the step by the suggestion of my friend, and thus, with the con- 
currence of Dr, Nansen’s splendid researches in the Polar Seas and off the coast of Norway, the past 
history of these regions will be very fully portrayed.’ 
1 Perhaps the most successful result of this orographic process is to be found in the representation of the mountains of Skye, known as the 
. rs + ‘ 
Cuchullin Hills, on the 6-inch Ordnance Survey Maps. 
2 The results as they were determined for successive areas were communicated in brief to Nature during 1898. 
8 “ Professor Hull’s Sub-Oceanic Terraces and River-Valleys off the Coast of Europe,” the American Geolgist, vol. xxxv., March 1905, p. 166 
A zi » Pp. 166. 
4 Since the above was written Professor Spencer has to a large extent carried out my wishes by writing for this monograph the final chapter. 
which adds much to the value and completeness of the work. ; 
° Bathymetrical Features of the North Polar Sea, Christiania, 1904. This work is reviewed by the author in the Geohgical Magazine, 
Decade V. vol. i. No. 482, 1904. : 
