JET. 72.] JULES MARCOU. 319 



years would no longer allow him to share with his 

 fellow-geologists in active field-work ; he had the ex- 

 perience of a long life, and the mass of unpublished 

 material was overwhelming. With the prospect of 

 speedy publication, he at once wrote to his friend of 

 many years, the late Professor Jules Marcou of Cam- 

 bridge, Mass., 1 for permission to make use of his map 

 of the world. 



OXFORD, 15th February 1884. 



MY DEAE M. MARCOU, Many thanks for the several Science 

 papers, [by] yourself and your son, that you have sent me, and 

 especially for your paper on the geology of California, recently 

 read. This paper interests me much, both with reference to 

 your account of the Glacial and Quaternary deposits, and with 

 reference to what you say about the age of the granite of the 

 Sierra Nevada. I was under the impression that the Jurassic 

 age of that granite had been well established, as it has been 

 generally received, but I see you give good reasons for ques- 

 tioning the conclusions. In fact, in writing on that subject a 

 short time since for a sort of text- book on Geology I have had 

 in hand for a long time past, I accepted the conclusion, and have 

 reasoned accordingly. This I must modify. In this work I also 

 am giving a small geological map of the world, reduced from 

 your large map, with a few additions, and proper acknowledg- 

 ment to you. As I shall be shortly putting it into the hands 

 of the artist, I should be very glad to know if you are bringing 

 out another edition, or if you have made any additions to that 

 capital piece of work that I could, with your permission, avail 

 myself of. I hope to have the pleasure of sending you a copy 

 of the first vol. of my work about the end of this year. I 

 get on but slowly, as I have to contend carefully against the 

 extreme Uniformitarian views which prevail in this country. 

 I trust you keep well. Mrs Prestwich desires her kind regards, 

 and I am, my dear Marcou, sincerely yours, 



JOSEPH PEESTWICH. 



Jules Marcou, born 1824 ; died April 18, 1898. 



