SKETCH OF ISAAC LEA. 407 



quest of Dr. Gray, Dr. Lea went over the collection of the Unionidce, 

 arranged and named them correctly, and added some new species from 

 the United States. He called, in Paris, on Baron Ferussac, the emi- 

 nent student of terrestrial and fluviatile mollusca, who was then en- 

 gaged in preparing his great work on the Unionidce. During the con- 

 versation the baron " complimented Dr. Lea by saying that he could not 

 go on with his work until he (Dr. Lea) had finished his memoirs." Dr. 

 Lea afterward spent several hours in going over the baron's collections, 

 which contained Unionidce from Brazil, Syria, Turkey, and Egypt, 

 and rearranging it, cutting down the species and forming numerous 

 synonyms. Afterward, he met Blainville, Ferussac, and others at the 

 Jardin des Plantes, to arrange and name all the Unionidce of the col- 

 lection there, to which he added fourteen species. From Studer, the 

 elder, in Berne, he received the last copy in the author's possession of 

 his work on the land and fresh-water shells of Switzerland, and com- 

 pliments on the papers he had himself written. At Paris, again, he 

 examined the Unionidce in the Due de Rivoli's collection, which con- 

 tained all those of Lamarck, and was thereby able to identify all of 

 Lamarck's species in his subsequent memoir. Calling on M. Gay by 

 invitation, he was shown all the mollusca which that naturalist had 

 collected in his travels, and was invited to select a specimen of each. 

 Thus he found the most eminent naturalists everywhere, on the 

 strength of the few papers he had published on American mollusca, 

 ready to welcome him as one of themselves, and to receive instruction 

 from him. Their general message to him was to go on with the in- 

 vestigations he had begun, with the assurance that no naturalist in 

 America or Europe had the advantages that he possessed. 



On returning home in November, 1832, he found that he had been 

 anticipated in a work he should have done on the Tertiary shells of 

 Alabama, but, having specimens of the species in his cabinet, he pre- 

 pared a paper, " Contributions to Geology," which he presented to 

 the Academy of Natural Sciences in August, 1833. It contained 

 two hundred and twenty-one species. His " Synopsis of the Family 

 Naiades," published in 1836, and afterward supplemented and ex- 

 panded, is said to have settled satisfactorily to most conchologists the 

 synonymy of the species. On receiving it, Prince Charles Bonaparte 

 expressed a desire to see all parts of zoology treated in the same man- 

 ner. In 1849 Dr. Lea presented a paper on the foot-marks of the reptile 

 Sauropus primcevus, found by him in the red shales at Pottsville, 

 Pennsylvania, seventeen hundred feet below the conglomerate, which 

 was of interest on account of the discussion it excited as to the age of 

 the fossil. The foot-prints were assigned to the old red sandstone, 

 while Professor Agassiz had declared that he did not believe that any 

 air-breathing animals had existed before the new red sandstone. The 

 discussion was kept up for several years, in the course of which Dr. 

 Lea reiterated and maintained his position that the fossil was what he 



