SUMMARY OF RESULTS. 
61 
The rise, during the fifteenth century, of Geology, which includes the oceanographical Risk of 
changes of past ages, gave an impetus to many questions relative to the distribution of 
land and water in past times, and led to an investigation of many phenomena in existing 
oceans. Leonardo da Vinci, in the fifteenth century, wrote that the sea changes the Vinci. 
equilibrium of the earth, that the shells accumulated in various layers have necessarily 
lived on a spot previously occupied by the sea ; that the great rivers carry into the 
ocean the waste of the land, and the deposits thus formed have been successively covered 
by others of varying thickness, and finally that the bottom of the sea has become the 
tops of mountains. 
Ever since that period researches have constantly been made by naturalists to dis- 
cover the relationship between the marine animals of our own time and those discovered in 
a fossil state. The name of Steno, a Dane, is associated with the evolution of general ideas Steno. 
as to the formation of the earth. In his famous work : De solido intra solidum naturaliter 
contento dissertation^ prodromus (1669), he endeavours to show that the carapaces of 
Crustacea are formed of matter secreted by the animal’s body ; he establishes the con- 
nection existing between fossils and the sedimentary layers containing them, and the true 
origin of both. He was the first to distinguish the layers formed in the sea from those 
deposited in fresh water, and to notice the character of the shells in both instances. He 
concludes, from his observations on the nature of these deposits, that the layers now 
found perpendicular or inclined were horizontal at the time of their formation. These 
changes in the position of land strata, considered as the primary cause of the earth’s 
inequalities, constitute the fundamental idea of Steno, and are now universally 
adopted. 
Geology received another great stimulus in Italy towards the middle of the eighteenth 
century, through the theoretical ideas of Ant. Lazzaro Moro, and still more through the Moro. 
observations of Arduino. In 1740 Moro developed a system in which he attributes to 
frequently recurring submarine explosions the formation of mountains, plains, and islands. 
The apparition of the small islands Mikra Kaumena and Nea Kaumena in the volcanic group 
of Santorin, and the phenomena which accompanied the formation of Monte Nuovo, seem 
to have given rise to this theory. According to Moro, the globe was primitively covered 
with water ; on the third day of creation the crust which formed the bottom of the sea 
was raised, the mountains resulting from this upheaval being the primitive rocks devoid of 
fossils. At a later period lava and other substances arose from the interior of the earth, 
and accumulated on the bottom of the sea, being upheaved in their turn through the same 
agency. With the rocks of this second upheaval diverse substances, such as salt, sulphur, 
and bitumen, were associated, and as a natural consequence the water became salt ; 
animals were developed in the sea ; the earth became peopled about the same time, and, 
the eruptions continuing, an alternation of sedimentary and eruptive deposits was 
produced. 
