LIFE OF JAMES DWIGHT DANA 



DANA TO JOHN W. JUDD 



" NEW HAVEN, September 4, 1891. 



" My long silence has been owing to impaired health 

 from overwork in the early autumn. Your very import- 

 ant article on quartz I was unable to notice in the Jour- 

 nal, and my son put the facts in the new edition of my 

 Mineralogy which he has now about two thirds through 

 the press. Since then I have been doing nothing until 

 recently, when, owing to improvement, I was able to 

 finish a paper half-ready before a copy of which I now 

 send you. The paper will show you that I find it hard 

 to be idle. 



" Before reading the paper you would do well to look 

 at page 20 of my Manual of Geology, where there is a 

 map showing the position of our West Rock ridge, and 

 its relations to the other Jura-Trias trap ridges of the 

 Connecticut Valley between New Haven and Hartford 

 (thirty-six miles). You will note that the section pre- 

 sented in Plate VII. is an east and west, or transverse, 

 section. North and south sections of the west side are 

 common. As there is no evidence whatever of displace- 

 ments in the trap, there is no doubt over the conclusion 

 that the sandstone was upturned before the outflow of the 

 trap. I wish you had come out to the International Con- 

 gress, that you might have seen our trap ridges, etc. 

 The Congress adjourned Tuesday, and Wednesday morn- 

 ing at nine o'clock a party of about eighty commenced 

 the excursion to the Yellowstone Park and other western 

 regions of interest. I was not well enough to be present, 

 although in a condition to do some work at home. My 

 troubles are a fatigued head rather than body, my limbs 

 still serving me well." 



DANA TO JOHN W. JUDD 



"NEW HAVEN, December 4, 1891. 



' It was a delight to me to receive your kind letter of 

 the 22d of September and to find myself thus again in 

 communication with the outer world. Since then I have 

 been gaining slowly, and now have out another paper on 

 the Connecticut Valley Rocks. In this paper I present a 



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