4 o8 THE POPULAR SCIENCE MONTHLY. 



represented it, and tbat the formation in which it was found was the 

 one indicated by Rogers as No. XI. Its interest has since been dimin- 

 ished by tbe discovery and authentication of fossils of air-breathers in 

 still older formations. Another series of papers of peculiar interest 

 was tbat concerning the fossil saurian of the new red sandstone 

 ( Clepsysaurus Pennsylvanicus). 



Having retired from business in 1851, Dr. Lea made another visit 

 to Europe in 1852. Many of the incidents of his previous visit were 

 substantially repeated, but in large part with naturalists of another 

 generation tban those whom he had met before. At Paris he arranged 

 and named the Unionidw in the cabinets of the eminent conchologists 

 Boivin and Petit. He called upon Dr. Cbenu to look for the original 

 specimen of Mulleria of Ferussac, which had never been figured, but 

 simply described as being in Lamarck's collection. " He told Dr. 

 Chenu that he thought it must have been mixed with the Etheria, of 

 which the collection had many specimens. Dr. Chenu declared this 

 could not be so, or he would have seen it. As soon as he pulled out 

 the drawer, Dr. Lea saw at a glance the identical specimen which 

 Ferussac had described. He took it up and declared this to be it. 

 Both the naturalists were surprised and delighted. . . . Thus Dr. Lea's 

 theory of the genus Acostea, of D'Orbigny, was complete it was a 

 Mulleria." At Vienna he showed the Austrian naturalists some feat- 

 ures in their species and specimens which had escaped their eyes. At 

 Berlin he found Humboldt and other distinguished men of science 

 much interested in what was going on in geology in the United States. 

 At a dinner with the Philosophical Club in London, Sir Charles Lyell 

 gave him credit for being the first and only one who had yet observed 

 an air-breathing animal in so ancient a rock as that in which the Sau- 

 ropus primcevus occurred, and added that the Clepsysaurus Pennsylva- 

 nicus was the first discovery of bones in the new red sandstone, although 

 a jaw of a similar animal had since been found. Colonel Sabine exhib- 

 ited a bottle which he supposed had come through Behring Strait from 

 Japan, which Dr. Lea was able to claim as a verification of his theory 

 of a west-to-cast Arctic current. 



On his return home in November, 1853, Dr. Lea found an accumu- 

 lation of correspondence and specimens awaiting his attention that 

 hardly diminished, so incessant were the fresh arrivals, during the 

 remainder of his active life, or for twenty-five years. Among his 

 new Southern and Southwestern correspondents was Bishop Elliott, of 

 Georgia, who became greatly interested in the mollusca of that State, 

 and engaged others in interest in the subject and in collecting shells. 

 The scientific researches of Dr. Lea were continued, with constant pub- 

 lications, until 1877, when a sudden illness which came upon him in 

 Southern California disabled him from further vigorous work. He 

 still, however, continued to add to his collections and perform such 

 work upon them as his strength would allow. He gave much attention 



