MEMOIR OF J. PETER LESLEY 537 



the several reports. The necessity for such summaries increased with 

 the number of volumes, for the districts were studied independently, and 

 no report was bound closely to those by other observers in neighboring 

 districts. These prefaces were steps toward a final report, enabling stu- 

 dents to utilize quickly the work done in an extended area showing the 

 same general phenomena. The labor involved in preparing them was 

 very great ; the manuscript of each report was read with the utmost care ; 

 the accompanying maps were studied with equal care, and not a few of 

 them were redrawn by Lesley himself, who prepared also many of the 

 elaborate indices — all this, that he make himself thoroughly familiar 

 with the details. 



How well he succeeded is shown by the final report, which, unfortu- 

 nately, he could not complete. He had finished the story to the end of 

 the Lower Carboniferous, when his health gave way, and the rest of the 

 work was prepared by others. In this report he summarized every vol- 

 ume ; he gives full credit to each member of his staff, while important 

 phenomena, observed by the assistants, receive full discussion from the 

 standpoints of his broad reading and his own field work. There is no 

 attempt to evade anything, no inclination to undervalue the work of 

 those disagreeing with him ; on the contrary, there is a frank presentation 

 of opposing views and frequently a retraction of opinions long held very 

 dear by him. The more than one hundred and twenty volumes of sur- 

 vey reports are his monument. 



Professor Lesley's power of endurance was almost equal to his indus- 

 try ; indeed, for many years his capacity for work seemed to be unlim- 

 ited ; but in the later sixties, during the early expansion of the oil indus- 

 try of Pennsylvania, the limit was reached and his health collapsed. 

 Recovery was very slow, but complete; thereafter he lived strictly by 

 rule. During the years 1874 to 1891, the active 3'ears of the second sur- 

 vey, he closed his office promptly at 4 o'clock, giving six hours of con-, 

 centrated labor daily. But the preparation of the final report required 

 haste, and his day knew no measure, with the result that in 1893 his life 

 as a student ended without warning. He was able to supervise matters 

 for almost two years longer, and then, the work having been completed, 

 he retired to Milton, Massachusetts, where the remaining years of his life 

 were spent in comfort amid scenes which had always been dear to him. 



Throughout Professor Lesley sought only to do to others as he would 

 have them do to him. If at times in a discussion he aimed directly at 

 the weak places in his adversary's armor and drove his weapon home 

 with his might, all knew that no rancor accompanied .the thrust. He 

 was but a champion defending the right, and he always recognized that 

 his adversary was equally honest, though of course on the wrong side. 



