LETTERS TO REV. GARDINER SPRING, D. D. 147 



first saw your collection many years ago. Has any reptile 

 three toes ? Has any reptile four ? 



The courtesy which Professor Silliman continued 

 to show toward clerical sceptics respecting geolog- 

 ical truth, even long after the main conclusions of 

 geology had been generally accepted among edu- 

 cated men, is illustrated in the following letters ad- 

 dressed to the venerable Dr. Spring, with whom he 

 had previously conferred on this subject. 



TO REV. GARDINER SPRING, D. D. 



NEW HAVEN, July 24, 1854. 



MY DEAR SIR, The enclosed little tract was written 

 fifteen years ago, and contains only an extremely condensed 

 statement of facts regarding the structure and age of the 

 earth, and it has been confirmed more and more by subse- 

 quent observations and discoveries. 



Should you find an unoccupied hour in which to give it 

 a perusal, you will perceive that the conclusions of geology 

 are the result of extended and honest investigation. In 

 these conclusions, as regards the extent and order of time, 

 all geologists agree, whatever hypotheses may have been 

 put forth by individuals upon particular subjects. This 

 little tract formed a preface to an edition, which I published, 

 of Dr. Mantell's " Wonders of Geology " ; it falls very far 

 short of a full presentation of the facts, of which another 

 tract of mine contains a more ample statement ; but the 

 perusal of this might impose too heavy a tax on your time. 

 Could I speak to you during the twenty-five daily lectures 

 which (D. V.) I expect to give in May next, (my conclud- 

 ing course,) with the aid of numerous fine drawings and all 

 requisite specimens, I trust I could convince you that geol- 

 ogy is not a dream, and that as believed and taught by re- 

 ligious men of competent attainments, it presents a demon- 



