3o6 The American Geologist. May, x^m 
"Syntrialasma hemiplicata," and is known as the Syntrialasma 
zone. The lower member is a buff limestone. 
luiwrence Shales. The name was first applied by Haworth, 
in 1894, to the greater part of the beds occupying the interval 
between what is believed to be the Plattsburg and Plattsmouth 
formations. It was afterwards extended to all the strata be- 
tween the two limestones. The maximum thickness is at least 
300 feet and in southern Kansas probably greater. Several 
limestone beds occur in it. Two have received in Kansas spe- 
cial designations, the Strawn and the Ottawa. On the Missou- 
ri river minor subdivisions are easily recognized over a wide 
area. The upper member is known as the Andrew shale, the 
median one the latan limestone, and the lower the Weston 
shale. These subdivisions are traceable for a long distance in- 
to Kansas. The exact relation of the limestone to the Strawn 
is not known, yet it is not believed to be the same. On the 
Kansas river a thin coal seam occurs in the upper part of the 
Lawrence. 
Platts)iwuth Limestone. The relations of the Carboniferous 
beds exposed in Nebraska to those farther down the Missouri 
river have never been considered. The rocks of the northern 
district have had a singular history. The typical section of 
the Plattsmouth early attracted attention. Owen visited the 
locality more than fifty years ago. From the same limestone, 
at Bellevue a few miles away, he collected numbers of char- 
acteristic fossils. He was of the opinion that all of the rocks 
exposed along this part of the Missouri river belonged to the 
Carboniferous limestone series (Mississippian). They are so 
colored on his map. The marked dip to the southward, which 
he observed below the mouth of the Platte river, probably was 
the chief factor that lead him to believe that the Coal Measures 
were deposited in a shallow saucer-shaped basin of which the 
opposite rim was near the Mississippi river. 
Although he mistook the limestone exposed at Bellevue to 
be the same as that at Parkville and Weston (Plattsburg lime- 
stone). Swallow considered all of these formations to lie above 
the productive coal measures, and he called them the Upper 
Coal series or Upper Coal Measures. During the same year 
(1855) there appeared a geological map of the United States, 
bv ]\Iarcou, in which these formations of the Missouri river 
