104 



ISLAND LIFE 



PART I 



that all sedimentary deposits have been formed under 

 water, but we also know that they were largely formed in 

 lakes or inland seas, or near the coasts of continents or 

 great islands, and that deposits uniform in character and 

 more than 150 or 200 miles wide were rarely, if ever, 

 formed at the same time. The further we go from the 

 land the less rapidly deposition takes place, hence the 

 great bulk of all the strata must have been formed near 

 land. Some deposits are, it is true, continually forming in 

 the midst of the great oceans, but these are chiefly organic 

 and increase very slowly, and there is no proof that any 

 part of the series of known geological formations exactly 

 resembles them. Chalk, which is still believed to be such a 

 deposit by many naturalists, has been shown, by its con- 

 tained fossils, to be a comparatively shallow water forma- 

 tion — that is, one formed at a depth measured by hundreds 

 rather than by thousands of fathoms. The nature of the 

 formations composing all our continents also proves the 

 continuity of those continents. Everywhere we find clearly 

 marked shore and estiiarine deposits, showing that every 

 part of the existing land has in turn been on the sea-shore ; 

 and we also find in all periods lacustrine formations of 

 considerable extent with remains of plants and land 

 animals, proving the existence of continents or extensive 

 lands, in which such lakes or estuaries could be formed. 

 These lacustrine deposits can be traced back through 

 every period, from the newer Tertiary to the Devonian and 

 Cambrian, and in every continent which has been geo- 

 logically explored ; and thus complete the proof that our 

 continents have been in existence under ever changing 



thesis." "We must leave it to our readers to decide whether the "notion" 

 developed in this chapter is "funny," or whether such hasty and superficial 

 arguments as those here quoted from a "practical geologist" have any 

 value as against the different classes of facts, all pointing to an opposite 

 conclusion, which have now been briefly laid before them, supported as 

 they are l3y the expressed opinion of so weighty an authority as Sir 

 Archibald Geikie, who, in the lecture already quoted says: — "From all 

 this evidence we may legitimately conclude that the present land of the 

 globe, though formed in great measure of marine formations, has never 

 lain under the deep sea ; but that its site must always have been near 

 land. Even its thick marine limestones are the deposits of comparatively 

 shallow water." 



