BRONN ON PAL.EONTOLOGICAL STATICS. 43 



fore, that these remains should come clown to us in a recognizable 

 condition, it is not only necessary that the}" should reach the water 

 and sink to the bottom of it whilst it was forming a deposit, but this 

 deposit must also be of that nature which is adapted for the preserva- 

 tion of that peculiar kind of organic remain ; it must exclude the 

 action of the air as well as of mechanical forces with sufficient rapi- 

 dity before these remains are decomposed or destroyed ; it must con- 

 solidate Avith sufficient quickness, or increase so slowly in weight as 

 not to crush them into a wholly undeterminable condition. The in- 

 habitants of the sea with characteristic, hard, earthy parts are much 

 more favourably situated. They occur always in the same element 

 from which the strata are deposited, and consequently are at all times 

 in a position to be enclosed in them. Let any one consider an ex- 

 isting continent and ask himself how many of its organic beings could 

 probably be recognized from their remains w^hich might be preserved 

 in the recent stratified formations of this continent, as for instance 

 in lakes, in river deposits, on the sea-coasts, or below mountain slips : 

 not a thousandth part of the species would be again distinguishable. 

 Let us imagine this continent sinking one portion after another, step 

 by step, below the sea, which along one part of the new coast soon 

 spreads out new strata over it, whilst on the shore all the organisms 

 sunk along with it lie open and uncovered, exposed to destruction 

 from the water and the ravages of its inhabitants. Kow small the 

 probability after a thousand years, supposing it possible to turn over 

 all these beds, that the remains found in them would enable us to form 

 an image of the former fauna and flora of this portion of the globe ! 

 But how little do we really know of the strata of the earth ! How large 

 is that part of the rock-formations of Europe, the interior of which is 

 unknown, compared with the strata which have been examined at their 

 outcrop ! And how much smaller is the portion of the earth's surface 

 examined in a similar manner in other quarters of the globe ! Finally, 

 should we attempt to institute a comparison between the distinguish- 

 able fossil beings and the present creation, what is the present creation ? 

 Does it consist of 100,000 or 200,000 species of animals, of 70,000 

 or 150,000 species of plants? and how many genera does it contain? 

 What is a species ? and wdiat indeed is a genus ? Cuvier twenty- 

 five years ago believed the surface of the earth so well explored, that 

 there was but little hope of many new species of large animals being 

 discovered. Now certainly the number of very large species has not 

 been great ; but the highest class of animals, the mammalia, has 

 since 1829 increased from 800 to 2000 species. The birds have 

 never been completely described. The work on the species of fish 

 is also still unfinished. Count Dejean has about 30,000 species of 

 Coleoptera alone in his collection, ten times as many as are known 

 in the whole class of the Diptera ; and yet Wurtemberg, which has 

 been carefully explored in regard to both classes by Roser, furnishes 

 at least full as many Diptera as Coleoptera. We have assumed the 

 number of genera of living insects quite arbitrarily at 4000 ; perhaps 

 we ought to assume .5000, 6000, 7000 or more ; the extent of a 

 genus is almost entirely arbitrary. And how shall we distinguish 



