THE 
AMERICAN NATURALIST. 
VoL. XXII. DECEMBER, 1888. No. 264, 
SURFACE GEOLOGY OF BURLINGTON, IOWA. 
BY CHARLES R. KEYES. 
HE sedimentary rocks of Burlington have afforded such unri- 
valed facilities for the study of an extensive piscine and crin- 
oidal fauna that attention has been almost totally diverted not 
only from other well represented faunal groups, but also the equally 
interesting stratigraphical and cenological features of that vicinity. 
While the palzontological researches were being so assiduously car- 
ried on, regional stratigraphy necessarily received, at divers times, 
more or less consideration, and is comparatively well understood. 
Recently a detailed investigation of the superficial deposits of the 
region was instituted, and a preliminary notice of the observations 
over a limited area is herewith presented. 
The general geographical features of the annexed map have been 
compiled from Powers’ map of the city of Burlington and a por= 
tion of the map of Des Moines county, as given in Andreas’ His- 
torical Atlas of Iowa. In a few minor particulars, observation has 
necessitated some corrections and additions. The hypsometrical 
features are approximately accurate—the contours (twenty feet apart) 
_ having been, for the most part, constructed from measured street 
and railway elevations, and, especially in the northern third of the 
area represented, from measurements personally made with level 
and rod. Over certain areas of limited extent estimates from points 
of prominence were also made. Along the eastern margins of North 
and Prospect hills the contours should in reality form a single line, — 
but it has been deemed more advisable, for reasons hereafter stated, 
