6 PROCEEDINGS OF THE DETROIT MEETING. 
the measured sections. These considerations justify the inference that the thick- 
ness of the Puget series may probably be 9,000 feet or more. 
STRUCTURE 
The strata of the Puget series were deposited upon the slowly subsiding bottom 
of the geosyncline between the axes of the present Cascade and Olympic ranges. 
As strata of similar composition and age are involved in the mass of the Cascade 
range, and probably also of the Olympics, the uplift of these mountains was to a 
greater or less extent accomplished after the Puget epoch. From asection observed 
immediately east of Renton, in which the highest strata of the Puget formation are 
in overthrust contact with conglomerates derived from the Puget rocks, it is in- 
ferred that the effort of compression took place in Miocene time. Asa result of 
this effort the Puget strata were more or less extensively folded, a process to which 
they readily yielded in consequence of the frequent interbedding of soft coal beds. 
The resulting folds differ in character in the several productive districts, being in 
the northern or Gilman field simply monoclinal; in the Green River field broadly 
flexed, and in the Wilkeson field closely appressed with extensive overthrust faults. 
The details of these structures are further complicated by normal faulting of later 
date and the intrusion of the igneous rocks of post-Miocene age. 
In general the axes of these folds trend north and south, parallel to the axis of 
the antecedent geosyncline, but there are evidences in local structures which show 
that the forces of compression were exerted also at right angles to the greater press- 
ure. In general terms, the structure may be described as that of the Appalachian 
type modified by the local peculiarities of stratigraphy which give it the specific 
characteristics of the anthracite coal fields. 
The detailed evidence on which these generalizations are based will be presented 
in the descriptions and maps in the article in the Eighteenth Annual Report of 
the United States Geological Survey. 
Remarks upon the matter of Mr Willis’ paper were made by E. W. 
Claypole. 
The paper will be printed in full in the Eighteenth Annual Report of 
the United States Geological Survey. 
The next paper was read by Mr Frank Leverett in the absence of the 
author. : 
LOESS AS A LAND DEPOSIT 
BY J. A. UDDEN 
Contents 
Page 
CO) on fEXeUMMODatS). Woy Ke fWIEXONTS) MOY) KOLO NVSYETES 5 ecean 95600 soocapcnococeoa0/NEeeoIAaRESCAND0oLGUD HabuaD sopEnN Jenna neasaAooHa=TEHAQ9OACENTE 6 
Adequacy of wind as shown im the Mississippi Vall yercccc.e.ee.c-sscc uaceetuseustesecacedes cversedereeeseeveevs 7 
Shooauilenmaliny Che Lopaaoxoyshheionar Cope Iexekys) AWaKEl CEI po ooc.doohonnnsoosbascesoonao0e ono nbabsuoucoohen: nod aAosnoApSsasASnpandanSnce s 
Otherifeammnesssusvainin ey eolianulaypothesiSenessssceesesssessereeereesaenetete nee eratneete cette een neeeeae 8 
OBJECTIONS ro AQurous Hypornmsis 
A study of the work of the wind as a geological, agent leads me to discuss the 
bearing this study appears to have on the deposition of the American loess. This 
