Leidy.] 40^ [Noy. is, 



He reached the advanced age, within a few mouths, of ninety-five 

 years, retaining to tlie last his intellect and his interest in his family, in 

 science and everything that had rendered him happy during life. He 

 died December 8lh, 1886. 



Mr. Lea was an enthusiastic student and an ardent lover of nature, and 

 though like most other people occupied for many of the best years of his 

 life with the exacting cares of business, he always found leisure success- 

 fully to pursue his studies and investigations in natural history. He was 

 especially interested in mineralogy, geology and palaeontology, but above 

 all delighted in and devoted most time to the study of the fresh-water 

 Mollusca, for which a favorable opportunity was afforded in the foct that 

 the great rivers of this country are particularly rich in these animals and 

 had been but imperfectly explored at the time of his taking up the study. 



To all the subjects. indicated and to others Mr. Lea has contributed to 

 our knowledge ; but to the last one in an eminent degree not excelled by 

 other naturalists. The record of this knowledge is contained in numer- 

 ous communications, for the most part published in the Transactions of 

 the American Philosophical Society and the Journal of the Academy of 

 Natural Sciences of Philadelphia. Mr. Lea was a most acute and accu- 

 rate observer and a most painstaking and conscientious investigator. Of 

 the fresh-water and terrestrial Mollusca, Mr. Lea has described upwards 

 of sixteen hundred new species of about fifty genera. The descriptions 

 are given in the most comprehensive manner with exhaustive detail, and 

 are accompanied with admirable illustrations. He was enabled to make 

 this large contribution to our knowledge from the fact that his name be- 

 came everywhere known as the leading authority in this department of 

 concliology, and collectors in every land eagerly submitted to him all 

 specimens supposed to be new or otherwise of scientific interest which 

 came into their hands. 



Of Mr. Lea's labors relating to the extensive family of freshwater 

 Mollusca, the Unionidic, Prof. Owen, of England, has expressed himself 

 in the following words : "You have set a noble example of iDcrsevering 

 devotion to the elucidation and making known to j^our fellow-men, of the 

 portion of God's creation selected by your judgment, taste and opportu- 

 nities for your studies. You will leave a grand and enduring monument 

 of what one man may accomplish under such conditions, and I trust you 

 may enjoy many years cheered by the retrospect of past labors, and by 

 the grateful estimation in which they are held by the naturalists and lov- 

 ers of science in both hemispheres." 



Mr. Lea's chief contributions to geology and palaeontology are found in 

 the following works : 



Contributions to Geology. 8vo. Philadelphia, 1833 ; 227 pages and 

 228 figures. This is one of the earliest and most extensive contributions 

 to a knowledge of the geology and fossils of the Tertiary formations of 

 this country. The work relates to the formations of Alabama, Maryland 



