4 INTRODUCTION. 



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

 And, in general, where Letter material cannot lie 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 hi 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 La melhbranchs, whose generic relations cannot be affirmed with certainty, are 

 passed over without notice, except two species which are simply 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 six, based upon casts, three are species 

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

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

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

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

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

 predecessors in palseontological study, — of having been obliged in some instances to 

 describe a species from a solitary example. 



Age of the Strata from which the Fossils were derived. 



Botta's Observations sur le Liban it VAntUiban, published in 1833 (Memoires de la 

 Societe" Geologique 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 Botta 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, w ith the aid of European collections, I'.ouc 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 Eeinrich yon Schubert and Professor Both visited Palestine, made a great 

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

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

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

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

 were widely adopted, bul were afterward discarded, and call Eoi no further notice. 



