SUMMARY OF RESULTS. 
101 
France, Delesse studied those of the Mediterranean, Atlantic, English Channel, German 
Ocean, and also the ancient seas and great lakes. He traces the orography of America, 
its hydrographic basins, and rainfall ; he gives a lithological description of the great 
North American lakes, Caribbean Sea, Gulf of Mexico, the American Atlantic Ocean 
from the West Indies to Labrador, part of the Arctic Seas, and the American Pacific 
Ocean. His results are given in three large maps, remarkable for their execution : 1st, of 
the French seas ; 2nd, of the European seas ; and 3rd, of the North American seas. He 
then applies himself to the study of the French seas during the principal geological 
periods, and in five special maps indicates the submarine orography of the Silurian, 
Triassic, Liassic, Eocene, and Pliocene seas. A sixth map affords a large amount of 
information relating to the depths of the French seas, the quantity of carbonate of 
lime in the coast sediments, the beds of shells, the distribution of the oyster, and the 
slow oscillations of the coasts. In seven tables he summarises his results as regards the 
relative frequency of the winds, the materials forming dunes, the distribution of rain, the 
river deposits, the deposits in littoral lakes and ponds, the littoral marine deposits, and 
the submarine deposits. 
The subject of deep-sea dredging was not neglected in Great Britain. In the 
autumn of 1868, in consequence of a suggestion of Professor Wyville Thomson to 
Dr. W. B. Carpenter, the Koyal Society laid before the Admiralty a statement of the 
advantages to science likely to result from a short dredging cruise in the North Atlantic. 
The Admiralty responded by placing the surveying ship “ Lightning,” Captain May, at “Lightning” 
the disposal of Drs. Thomson and Carpenter. The conditions of work in the “ Lightning ” Expedition - 
were very unfortunate both as regards the vessel and the weather which prevailed 
during the six -weeks that the cruise lasted. In spite of all difficulties, dredging 
was carried on to a depth of 650 fathoms, and temperature results of the greatest 
interest were observed, which ultimately led to the discovery of the Wyville Thomson Wtville Thom- 
Ridge in the Faroe Channel in 1880 by Tizard and Murray. Professor WyviUe 
Thomson thus sums up the results of the “ Lightning ” expedition : — Deep-Sea Explor- 
“ It had been shown beyond question that animal life is varied and abundant, repre- A - 1;N - 9 
sented by all the invertebrate groups, at depths in the ocean down to 650 fathoms at 
least, notwithstanding the extraordinary conditions to which animals are there 
exposed. 
“ It had been determined that, instead of the water in the sea beyond a certain 
depth varying according to latitude having a uniform temperature of 4 C C., an indraught 
of Arctic water may have at any depth beyond the influence of the direct rays of the sun 
a temperature so low as — 2° C.; or, on the other hand, a warm current may have at any 
moderate depth a temperature of 6° '5 C., and it had been shown that great masses of 
water at different temperatures are moving about, each in its particular course ; maintain- 
ing a remarkable system of oceanic circulation, and yet keeping so distinct from one 
