Correspondence. 393 
CORRESPONDENCE. 
Block Mountains in New Mexico: A Cokrection. In the article 
entitled "Laws of Formation of New Mexico Mountain Ranges,'" print 
ed in the May nnmbcr of the Geologist, an omission of a line in the 
manuscript on page 308, second line from the bottom, destroys the sense. 
The passage should lead: "that the Rio Grande occupies a great anti- 
cline and that the strata would be found repeated in the reverse sense 
on the east side of the river." The passages referred to are in an ar- 
ticle en the Socorro and Linitar mountains printed in the Bulletins 
of Denison University and also in vol. i of the Bulletin of che 
University of New Mexico. One of them runs as follows: 
*''i"he pri'^cni course of the Rio Ginndc in central New MexiiV' oocu- 
I)ies what may (incc have been the axis nf su;:!' a fold, while the 
intersection of tlio western declivity with the present general level 
is marked by a fracture zone in which lie the chief centers of over- 
flow." 
The rule in Now Mexico is tbat the minor elevitions ar" m'.>noclincs 
and in this case also the anticline is not simple, but is compli:ated by 
extensive monoclinal axes of subordinate faulliiit^ on either side of 
the greater (anticlinal ) axis. c. l. hekkick. 
The Loess. The interesting articles of Prof. Wright and of Miss 
Owen in the April number of the Geologist express my views and 
fully coincide w^ith the conclusions I had arrived at over twenty years 
ago regarding such deposits rlong the Missouri. I have been familiar 
with the Missouri river for forty-five years and until two years ago I 
made trips on Missouri steamboats every year for fifteen years from its 
mouth to Kansas City and St. Joseph. 
Von Richthofpen viewed China from a very plausible staniliioint as 
mentioned by professor Wright. In 1877 Von Richthofen published 
a book on China in which he advanced his seolian theory, and consid- 
ered that if it was true in China, it would prove so everywhere else. 
In the .Imcrican Journal of Science, in 1879, professor E. W. Hil- 
gard had an instructive article on the loess of the Mississippi valley in 
which he supports the aqueous theory of the origin of the Loess. 
In the same volume of the Journal there is a notice of similar views 
advanced by J. E. Todd before the American Association, also support- 
ing the aqueous theory. 
In the same volume of the American Journal of Science the writer 
had an article also supporting similar views. In this I was supported 
by the late J. D. Dana. I have seen the loess from near the head of 
the Missouri to its mouth, and have seen good evidence of stratification 
in it, which could only take place by the agency of water. At St. 
Charles, Missouri, near the Wabash depot, there are seen pltemate 
beds of clay and sand evidently proving different periods of deposit. 
On the recently formed hanks of the Missouri are seen deposits 
lying horizontal and of uniform thickness and ench layer easily .t-cparate 
