E. W. CLAYPOLE — CONTINENTS AND DEEP SEAS. 13 



the sediments of such old systems as the Cambrian and Ordovician were formed at great depths, 

 and that they represent the modern abyssal clays." " This is particularly the ease with some of the 

 fine-grained muds, re9, brown or green, which occasionally form a conspicuous feature in the 

 Cambrian and Ordovician series. Such muds are not only singular for their extraordinary barren- 

 ness in fossils, but there is good ground for thinking that they have been formed by the decompo- 

 sition of volcanic matter, while they commonly exhibit dendrites of manganese." 



The deposits above 2,500 fathoms not unfrequently consist largely of radiolarian 

 and diatomaceous oozes, and these may be paralleled by similar deposits amonc; the 

 older strata. Haeckel regards the well-known " Barbadoes earth " as a deep-sea de- 

 posit, and states that many of the radiolarians of that island are to-day unchanged 

 in the radiolarian ooze of the deep Pacific ocean. 



But, setting these considerations on one side, there are some others. The lack of 

 what we should at once call deep-sea deposits among the strata may have been due to 

 the shallowness of the waters and be rather an evidence of the absence of ocean 

 abysses than of their permanence. This, if not a probable explanation, is at least pos- 

 sible, and the more so when we reflect on the comparatively small portion of our seas 

 over which the deep-sea deposits prevail. Again, it may result from our ignorance 

 of the contents of the rocks over a large part of the globe ; and we must also bear in 

 mind the fact that such deposits must be in most cases quite thin. Away from land- 

 wash, and dependent for their accumulation on volcanic and cosmic supplies, they 

 cannot be heavy. Were it otherwise, and had the abysses existed from the beginning, 

 they must have been long ago filled up. Moreover, the "Challenger " results have 

 shown us that fossils have been lying on the bed of the sea in some places ever since 

 the Eocene era without being buried. Atone haul of the dredge there were brought 

 up 600 shark teeth, 100 ear-bones of whales, and 50 fragments of bone; and many 

 of these specimens are identical with fossils found in the Eocene strata — Carcharodon 

 ■megalodon, for example. In this instance the deposition must have been exceedingly 

 slow. 



Further, in the discussion of this subject we might, if space allowed, dwell on the 

 fact that the red clays do not indicate deep water, except in a sea peopled with cal- 

 careous organisms. Apart from this, they prove merely distance from land. Ac- 

 cording to the "Challenger" reports, blue and green muds are forming around the 

 land to the depth of about 500 fathoms. Outside of this limit, therefore, in a sea not 

 thickly peopled with foraminifera, the deposits should resemble those of the deep sea. 



It might further be urged that strata so excessively thin as in many cases these 

 abyssal deposits must be might easily be eroded or concealed during the elevation of 

 the deep basin in which they were formed. 



Yet once more it will not be wise to proceed on the assumption, as do the advocates of 

 the permanence theory, that the present conditions of the globe have always prevailed. 

 Indeed some are so strongly of an opposite opinion that they do not hesitate to assert 

 that the present climates of the earth are quite exceptional, and that a very different 

 state of things existed in past ages at the poles not only transitorily (of which there is 

 no doubt) but even permanently, Now in this case the present condition of the bot- 

 tom of the deep sea with its cold currents cannot have been the lasting one, and it 

 would be unsafe to infer that the same deposits that are now and have been forming 

 there during the later geological eras were laid down during the earlier and especially 

 during the Palaeozoic days. 



(c) A third argument, and one on which great stress is laid in defense of perma- 

 nence, is the alleged absence from all true oceanic islands of the stratified rocks of 

 which the continents largely consist. It is even asserted that with one or two insig- 

 nificant exceptions all these are volcanic. 



