W4 2^he Am,erican Geologist. May, 1897 
PHYSIOGRAPIC GEOLOGY OF THE PUGET 
SOUND BASIN. 
By James P. Kimball, New York. 
(Plato XIX.) 
(^Continued from page 287.) 
The physiographic history of the Puget sound basin, broad- 
ly considered, from early Cretaceous well into Pleistocene 
time, is more than ordinarily incidental to oscillations of level. 
For the Cretaceous part of that interval the excessive alter- 
nations of the Puget coal series bear witness to this fact. 
The several occurrences of this series in western Washing- 
ton may collectively be described as relics of an extensive de- 
velopment of carbonaceous strata which have been involved in 
the overwhelming vulcanism of the region, referable to differ- 
t-nt epochs of the Tertiary period. Subaerial denudation fol- 
lowing close upon disruption, and eventually succeeded by a 
sweeping glacial erosion, has cleared the surface of all but iso- 
lated remnants. These have escaped destruction through de- 
fensive environment of masses of eruptives of subsequent age, 
and also to some extent through corrugation and profound 
local depression. Taken as a whole, and regarded as origin- 
ally a more or less continuous series, it is represented by differ- 
ent fragmental sections, mostly monoclinal, in individual 
areas. Known exceptions to the prevailing monoclinal struc- 
ture are the Wilkeson-Burnett-Pittsburg folds and the elevated 
Sugar Loaf basin. The McKay "basin," as at first described, 
has proved no exception to the rule. The diverse physical 
and chemical characters possessed by the coals and lignites in 
separate developments have obviously been more or less deter- 
mined by relations to eruptives, and as usual by relative 
degree of flexure. 
Almost every coal seam of each local section examined b}' 
the writer, is to a remarkable extent, an alternation of car- 
bonaceous, with more or less sedimentary, material. Excep- 
tions to this mode of occurrence in favor of particular devel- 
opments are rare. Close and systematic comparisons of 
disconnected sections remain to be instituted for purposes of 
correlation. Such inquiries are not without difficulty owing 
to a general absence of persistent divisional members, like 
limestones, ironstones and conglomerates, so useful for orien- 
tation. The physical constitution of the whole series, where- 
