THE 



PHILOSOPHICAL MAGAZINE 



AND 



ANNALS OF PHILOSOPHY. 



[NEW SERIES.] 



FEBRUARY 1830. 



A^ 



XI. Notes on the Geographical Distribution of Organic Re- 

 mains contained in the Oolitic Series of the Great London 

 and Paris Basiii, and in the saine Scries of the South of 

 France. By Henry T. Dela BECHE,i^7i..S. <§t.* 



T the present time, when rocks, so dissimilar in their miner- 

 alogical character and thickness, are referred to the same 

 geological epochs, from the nature of their organic remains, 

 it becomes important to ascertain, as far as our information 

 will permit, to what extent the opinions usually entertained on 

 this head are well founded; and if they should appear to be 

 only partially correct, to determine to what distances, fossils, 

 supposed characteristic, may be available. Many serious diffi- 

 culties attend an examination of this nature, 1st, Very able 

 observers of rocks may not be good zoologists, or may not 

 have had the fossils obtained by them from particular strata, 

 determined by those that are. 2ndly,We want synonyms for 

 the same shells to which different names have been assigned 

 by different authors. 3rdly, We do not possess complete lists, 

 even of the fossils found at various known places. And 4thly, We 

 cannot state that any given fossil discovered in one rock may 

 not occur in another because not yet found in it. We are 

 however in general furnished with lists of those fossils which 

 occur most abundantly at any given place ; and the organic 

 remains, supposed characteristic, are most frequently detailed, 

 from the very general desire, now existing among geologists, 

 to adopt this mode of identifying strata, so that, notwith- 

 standing the difficulties above enumerated, we may, by com- 

 paring the lists of those on whose accuracy we can depend, 

 arrive at some useful concluiions respecting the geographical 

 distribution of organic remains in a given group of rocks. 



• Communicated by the Author. 

 N.S. Vol. 7. No. 38. Feb. 1830. M M.Eli 



