A Notable Ride. — Calvin. 373 
hood are many picturesque escarpments and buttressed walls 
and bastioned fortresses, carved by natural processes from the 
living rock, and lending charm and variety to this unicjue drift- 
less landscape so strangely set in the midst of the great prairie 
plains of the middle west. 
Before reaching Julien, the surface inequalities become 
toned down to a marked extent. The relief is very much less. 
The outlines of the hills are more flowing, the curves more 
gentle. The weather-beaten crags disappear. The surface is 
yet rolling and irregular as compared with the ordinary prai- 
rie; but the land is susceptible of cultivation to a greater or less 
extent, and most of it has been brought under the plough. 
The ascending grade of the small valley followed by the rail- 
way brings the surface here above the upper limit of the Galena 
limestone, up to the softer Maquoketa shales; and it is this 
shale formation that expresses itself in the cliflfless, cragless, 
softened landscape. The billowy surface bears little resem- 
blance, however, to even an eroded drift plain. There is a cer- 
tain tumultousness and confusion manifest in the swells 
which mark the surface. There is no common level to which 
their summits rise; but a knob here and a ridge there may 
stand conspicuously above all the rest, and it is impossible to 
pick out any set or series anywhere, which can be referred to a 
common plane. The valleys of the larger streams are cut well 
below the general level of the region, the process of peneplan- 
ation is yet far from being complete, and the confused appear- 
ance of the land swells is due to the fact that the various parts 
of the surface are not being degraded at the same rate. 
A few miles west of Julien, and sweeping around in a long 
prominent ridge a mile or two south of the railway line, are the 
abrupt slopes and clififs of the Niagara limestone which overlies 
the Maquoketa shales. The Niagara, like the Galena, is dolo- 
mitic. It resists weathering and forms mural cliffs only sUght- 
ly less pronounced than those of the older and more perfectly 
crystalline dolomyte already noticed. The total thickness of 
the Maquoketa formation is something more than two hundred 
feet, but the area in which the shales are superficial — the area 
between the outcrops of the upper beds of the Galena and the 
base of the Niagara clilTs — is comparatively narrow, rarely ex- 
ceeding three miles in this part of Dubuque county. All 
