TOPOGRAPHICAL SUBDIVISIONS. 455 



the length of the valley between the two quartzite ranges, whose top- 

 ography has already been sufficiently indicated. About midway in. 

 the east and west length of this valley the western limit of the gla- 

 cial drift is met with, which is here in a morainic condition. Cross- 

 ing now to that portion of Sauk county which lies to the south of the 

 limestone-capped divide in the towns of Westfield and Franklin, and 

 of the southern quartzite range, we reach a part of the valley of the 

 Wisconsin itself, which may be designated as the Honey Creek dis- 

 trict (5). On the west side of this triangular area we find deeply 

 eroded valleys with limestone-capped separating ridges; further 

 south and east towards the river, numerous outliers and peculiar nar- 

 row ridges are seen; farther east still these cease suddenly, and on 

 the wide prairie in the towns of Prairie du Sac and Sumpter, morainic 

 drift begins as suddenly again. Along the Wisconsin in the south- 

 west corner of this area, the limestone-capped bluffs of an immense 

 outlier bound the river bottom for a number of miles. We have yet 

 to consider the last of these subordinate areas, (6) which includes 

 that portion of Marquette county south of the Fox river, and the 

 northern, central and western towns of Columbia county, being lim- 

 ited on the east and south by the western face of the limestone divide 

 between the Wisconsin and Rock rivers. This is an area in general 

 level, having an elevation of about 250 feet, with many bold lime- 

 stone outliers. It is drift covered, showing numerous large bowlders, 

 has everywhere a sandy soil, and a somewhat sparse growth of small 

 oaks. 



The third and last of the great topographical subdivisions of Cen- 

 tral Wisconsin we may designate as the limestone district, since in 

 it one or other of the Silurian limestones is almost always the surface 

 rock. It includes eastern and southern Columbia, and all of Dane, is 

 characterized nearly everywhere by an excellent soil, includes the 

 largest prairie areas of central Wisconsin, shows a prevailing growth 

 of oak, and has a rolling and diversified surface. The drift materials 

 are everywhere present, except in the southwestern towns of Dane, 

 which show the usual abrupt topography of the driftfess area. On 

 the northern side of this district, in the towns of Scott, Randolph, Court- 

 land, Otsego, Lowville, Hampden, Leeds and Arlington, in Columbia 

 county, and of Vienna, Westport, Dane, Springfield and Middleton, 

 in Dane county, there is a nearly continuous belt of high rolling prai- 

 rie from about 400 to 600 feet in altitude. The underlying rock on 

 this prairie is limestone, and the soil of the very best quality. From 

 the east and south flanks of this high land the country descends 

 rapidly, and is watered by the various head streams of Rock river. 



