Pembina Region of North Dakota— Berkey. 149 
whole series represented in the dissection of the second 
mountain may be tabulated as follows : 
Glacial drift, variable in thickness and character 0-25 ft. 
Gray to black brittle shales 300 ft. 
Black and white bands 6 ft. 
Cretaceous J Brown iron and gypsum bed 4 ft. 
Shales \ Yellow and bluish massive marls .... 150 ft. 
Black and greenish gray lamin- 
ated clay shales 250 ft. 
Of these the last two are of special interest because of 
their economic promise. By far the best outcrops of these 
are in the north bluff of the river just opposite the mouth of 
Little Pembina in sections 33 and 34, T. 163, R. 57, Cavalier 
Co.., N. D. This locality has many other advantageous feat- 
ures that scarcely come within the province of a geologic 
paper, such as feasability of railway connections, the prox- 
imity to a local wood supply, and the possibility of securing 
abundant water power by a dam across the river. At this 
point glacial and pre-glacial erosion has removed the upper 
beds of the series, as outlined above, leaving only the two 
lower members, i. e., 250 feet of clay shales and 100+ feet of 
cement marls capped directly with 10 to 20 feet of drift. 
Cement Maris, — Local interest following the impetus of 
the Tongue river development centered in the marls at first, 
and these beds not only here but along the whole escarpment 
and river have been repeatedly tested by numerous prospec- 
tors with a view to cement manufacture. There are zones 
in these marls whose lime content brings them within the 
class of cement rock. A long series of rough tests in the 
field, made by the writer, with crude equipment, for the pur- 
pose of limiting the horizons, gave fairly good and decisive 
results. Samples were oven dried and weighed and the con- 
stituents soluble in cold dilute hydrochloric acid were dis- 
solved out. Then the residues were burned and weighed as 
representing approximately the sand and clay content, 
while the difference in weight was taken to roughly measure 
the maximum possible lime content. This rapid preliminary 
testing proved very useful and served finally to locate shales 
of a quality that were not thought to exist in this region. 
A series of 35 samples of the marls gave a range of: 
i 
