468 Reports and Proceedings — 



palaeontologist, M. Barrande, amongst the Palaeozoic rocks of Bohemia, 

 though even these are gradually being reduced in number owing to recent 

 discoveries ; indeed, in the case of the marine faunas, marked cases of 

 recurrence are comparatively rare, and the occurrence of each form is 

 generally fairly unbroken from its first appearance to its final extinct inn, 

 thus showing that the imperfection of the record is by no means bo marked 

 as might be supposed. Fresh-water and terrestrial forms naturally furnish 

 a large percentage of cases of recurrence, owing to the comparative rarity 

 with which deposits containing such organisms are preserved amongst 

 the strata. 



A brief consideration of the main reasons for the present imperfection 

 of our knowledge of the faunas of rocks formed subsequently to pre- 

 Cambrian times may be useful, and suggestive of lines along which future 

 work may be carried out. That detailed work in tracts of country which 

 are yet unexplored, or have been but imperfectly examined by the geologist, 

 will add largely to our stock of information, needs only to be mentioned ; 

 the probable importance of work of this kind in the future may be inferred 

 from a consideration of the great increase of our knowledge of the Permo- 

 Carboniferous faunas, as the result of recent labours in remote legions. 

 It is specially desirable that the ancient faunas and floras of tropical 

 regions should be more fully made known, as a study of these will probably 

 throw considerable light upon the influence of climate upon the geographical 

 distribution of organisms in past times. The old floras and faunas of 

 Arctic regions are becoming fairly well known, thanks to the zeal with 

 which the Arctic regions have been explored. But, confining our attention 

 to the geology of our own country, much remains to be done even here, 

 and local observers especially have opportunities of adding largely to our 

 stock of knowledge, a task they have performed so well in the past. To 

 give examples of the value of such work, our knowledge of the fauna of 

 the Cambrian rocks of Britain is largely due to the present President of 

 the Geological Society, when resident at St. David's, whilst the magnificent 

 fauna of the Wenlock Limestone would have been far less perfectly known 

 than it is if it were not for the collections of men like the late Colonel 

 Fletcher and the late Dr. Grindrod. Again, the existence of the rich 

 fauna of the Cambridge Greensand would have been unsuspected, had not 

 the bed known by that name been worked for the phosphatic nodules 

 which it contains. 



It is very desirable that large collections of varieties of species should 

 be made, for in this matter the record is very imperfect. There has been, 

 and, I fear, is still, a tendency to reject specimens when their characters 

 do not conform with those given in specific descriptions, and thus much 

 valuable material is lost. Local observers should be specially careful to 

 search for varieties, which may be very abundant in places where the 

 conditions were favourable for their production, though rare or unknown 

 elsewhere. Thus, I find the late Mr. W. Keeping remarking that " it is 

 noteworthy that at TJpware, and, indeed, all other places known to me, 

 the species of Brachiopoda [of the Neocomian beds] maintain much more 

 distinctness and isolation from one another than at Brickhill." ' The 

 latter place appears to be one where conditions were exceptionally favour- 

 able in Neocomian times for the production of intermediate forms. 



A mere knowledge of varieties is, however, of no great use to the 

 collector without a general acquaintance with the morphology of the 

 organisms whose remains he extracts from the earth's strata, and one 

 who has this can do signal service to the science. It is specially important 

 that local observers should be willing to devote themselves to the study 

 of particular groups of organisms, and to collect large suites of specimens 



1 W. Keeping, Sedgwick Essay: "The Fossils and Palffiontological Affinities of 

 the Neocoinian Deposits of Up ware and Brickhill." Cambridge, 188S. 





