[if] as during subsidence favourable, accords with facts of European deposits112, but subsidence apt to destroy agents which produce sediment113.
I believe safely inferred «that» groups of marine «?» fossils only preserved for future ages where sediment goes on long «and» continuous«ly» and with rapid but not too rapid deposition in «an» area of subsidence. In how few places in any one region like Europe will «?» these contingencies be going on? Hence «?» in past ages mere [gaps] pages preserved114. Lyell's doctrine carried to extreme, – we shall understand difficulty if it be asked: – what chance of series of gradation between cattle by «illegible» at age «illegible» as far back as Miocene115? We know then cattle existed. Compare number of living, – immense duration of each period, – fewness of fossils.
This only refers to consecutiveness of history of organisms of each formation.
The foregoing argument will show firstly, that formations are distinct merely from want of fossils «of intermediate beds», and secondly, that each formation is full of gaps, has been advanced to account for fewness of preserved organisms compared to what have lived on the world. The very same argument explains why in older formations the organisms appear to come on and disappear suddenly, – but in [later] tertiary not quite suddenly116, in later tertiary gradually, – becoming rare and disappearing, – some have disappeared within man’s time. It is obvious that our theory requires gradual and nearly uniform introduction, possibly more sudden extermination, – subsidence of continent of Australia &c., &c.
Our theory requires that the first form which existed of each of the great divisions would present points intermediate between existing ones, but immensely different. Most geologists believe Silurian117 fossils are those which first existed in the whole world, not those which have chanced to be the oldest not destroyed, – or the first which existed in profoundly deep seas in progress of conversion from sea to land: if they are first they «? we» give up. Not so Hutton or Lyell: if first reptile118 of Red Sandstone «?» really was first which existed: if Pachyderm119 of Paris was first which existed: fish of Devonian: dragon fly of Lias: for we cannot suppose them the progenitors: they agree too closely with existing divisions. But geologists consider Europe as «?» a passage from sea to island «?» to continent (except Wealden, see Lyell). These animals therefore, I consider then mere introduction «?» from continents long since submerged.
Finally, if views of some geologists be correct, my theory must be given up. [Lyell’s views, as far as they go, are in favour, but they go so little in favour, and so much more is required, that it may «be» viewed as objection.] If geology present us with mere pages in chapters, towards end of «a» history, formed by tearing out bundles of leaves, and each page illustrating merely a small portion of the organisms of that time, the facts accord perfectly with my theory120.
Extermination. We have seen that in later periods the organisms have disappeared by degrees and [perhaps] probably by degrees in earlier, and I have said our theory requires it. As many naturalists seem to think extermination a most mysterious circumstance121 and call in astonishing agencies, it is well to recall what we have shown concerning the struggle of nature. An exterminating agency is at work with every organism: we scarcely see it: if robins would increase to thousands in ten years how severe must the process be. How imperceptible a small increase: fossils become rare: possibly sudden extermination as Australia, but as present means very slow and many means of escape, I shall doubt very sudden exterminations. Who can explain why some species abound more, – why does marsh titmouse, or ring-ouzel, now little change, – why is one sea-slug rare and another common on our coasts, – why one species of Rhinoceros more than another, – why is «illegible» tiger of India so rare? Curious and general sources of error, the place of an organism is instantly filled up.
We know state of earth has changed, and as earthquakes and tides go on, the state must change, – many geologists believe a slow gradual cooling. Now let us see in accordance with principles of [variation] specification explained in Sect. II. how species would probably be introduced and how such results accord with what is known.
The first fact geology proclaims is immense number of extinct forms, and new appearances. Tertiary strata leads to belief, that forms gradually become rare and disappear and are gradually supplied by others. We see some forms now becoming rare and disappearing, we know of no sudden creation: in older periods the forms appear to come in suddenly, scene shifts: but even here Devonian, Permian &c. [keep on supplying new links in chain] – Genera and higher forms come on and disappear, in same way leaving a species on one or more stages below that in which the form abounded.
«Geographical Distribution.»
§ VI. Let us consider the absolute state of distribution of organisms of earth's face
Referring chiefly, but not exclusively (from difficulty of transport, fewness, and the distinct characteristics of groups) to Mammalia; and first considering the three or four main [regions] divisions; North America, Europe, Asia, including greater part of E. Indian Archipelago and Africa are intimately allied. Africa most distinct, especially most southern parts. And the Arctic regions, which unite N. America, Asia and Europe, only separated (if we travel one way by Behring’s St.) by a narrow strait, is most intimately allied, indeed forms but one restricted group. Next comes S. America, – then Australia, Madagascar (and some small islands which stand very remote from the land). Looking at these main divisions separately, the organisms vary according to changes in condition122 of different parts. But besides this, barriers of every kind seem to separate regions in a greater degree than proportionally to the difference of climates on each side. Thus great chains of mountains, spaces of sea between islands and continents, even great rivers and deserts. In fact the amount «of» difference in the organisms bears a certain, but not invariable relation to the amount of physical difficulties to transit123.
There are some curious exceptions, namely, similarity of fauna of mountains of Europe and N. America and Lapland. Other cases just «the» reverse, mountains of eastern S. America, Altai «?», S. India «?»124: mountain summits of islands often eminently peculiar. Fauna generally of some islands, even when close, very dissimilar, in others very similar. [I am here led to observe one or more centres of creation125.]
The simple geologist can explain many of the foregoing cases of distribution. Subsidence of a continent in which free means of dispersal, would drive the lowland plants up to the mountains, now converted into islands, and the semi-alpine plants would take place of alpine, and alpine be destroyed, if mountains originally were not of great height. So we may see, during gradual changes126 of climate on a continent, the propagation of species would vary and adapt themselves to small changes causing much extermination127. The mountains of Europe were quite lately covered with ice, and the lowlands probably partaking of the Arctic climate and Fauna. Then as climate changed, arctic fauna would take place of ice, and an inundation of plants from different temperate countries «would» seize the lowlands, leaving islands of arctic forms. But if this had happened on an island, whence could the new forms have come, – here the geologist calls in creationists. If island formed, the geologist will suggest «that» many of the forms might have been borne from nearest land, but if peculiar, he calls in creationist, – as such island rises in height &c., he still more calls in creation. The creationist tells one, on a «illegible» spot the American spirit of creation makes Orpheus and Tyrannus and American doves, and in accordance with