4 INTRODUCTION. 



imperfect." (Quarterly Journal of the Geological Society of London, V, p. 376, 1849.) 

 And, in general, where better material cannot be obtained, if species are named with 

 proper care and discrimination from casts distinctly recognizable as to their genera, well 

 preserved, and possessing some striking and characteristic features, due regard being had 

 to the nature of the test in the group to which they belong, it would seem that such 

 species may be useful in studying the relations of the different beds in which they occur. 



The foregoing remarks, however, have been suggested by general considerations more 

 than by the demands of the work here recorded, as will appear from the following state- 

 ment. Of the fossils subjected to examination, the most obscure casts, Gasteropods as 

 well as Lamelhbranchs, whose generic relations cannot be aflirmed with certainty, are 

 passed over without notice, except two species which are siuaply figured and referred to 

 as indeterminate. Fourteen species of Gasteropods are described as new, of which all the 

 specimens used for the descriptions and figures, retain the shell, and generally in satisfac- 

 tory condition. Of sixteen new Lamellibranchs, ten species are described and figured 

 from specimens bearing the shell, and of the other sis, based upon casts, three are species 

 of the thin-shelled Plwladomyidce and Anatinidce, and concerning only one of the three 

 remaining can there be any doubt, if specimens of the species shall be found here- 

 after with the test preserved, that both shell and cast can be readily identified as of the 

 same species, thus involvmg neither confusion nor unnecessary change in specific names. 

 We have to regret the disadvantage under whicli we have labored, — shared with many 

 predecessors in palasontological study, — of having been obliged in some mstances to 

 describe a species from a solitary example. 



Age of the Strata from which the Fossils tvere derived. 



Botta's Observations sur le Lihcm ct I'Antilihan, published in 1833 (Memoires de la 

 Society G(5ologique de France, I, pp. 135-160), give the results of the first geological 

 exploration of the region to which they relate. The sections in detail, and the geological 

 plan, which accompany this excellent memoir, are still regarded as giving a correct idea 

 of the actual succession of formations in the mountain chains. But concerning the age 

 of those formations a change of opinion has followed upon later investigations. The 

 rocks and fossils collected by Eotta were submitted to Ami Bone, a learned geologist of 

 his time and secretary of the Geological Society of France. Having made a comparative 

 study of the specimens, with the aid of European collections, Boue came to the conclusion 

 that the three terrains of Lebanon recognized by Botta correspond to the Upper Jurassic, 

 the Greensand, and the Lower Chalk of European systems. 



In 1837 Heinrich von Schubert and Professor Roth visited Palestine, made a great 

 number of geological observations, and described various fossil beds in tlie Lebanon and 

 Anti-Lebanon ranges. Roth took back with him to Germany many fossils. About the 

 same time Russegger, an Austrian Councillor of Mines, made extensive journeys in Egypt, 

 the Soudan, and Syria, includmg Lebanon and Anti-Lebanon. His opinions for a time 

 were widely adopted, but were afterward discarded, and call for no further notice. 



