828 Gi tale SQW 
to the time of the river gravels, but must be assigned to some 
earlier period. 
Unstratified beds.— Overlaid by the stratified beds where they 
occur, otherwise by the loess, are certain deposits, which more 
especially form the subject of this article. They are confined to 
the valleys, where they have a much greater range than the strat- 
ified beds, reaching from two hundred feet or more above 
present river level to an unknown depth below. They consist 
characteristically of an aggregation of stones large and small 
together with the finer material forming the matrix. Although 
there is a considerable range of variation in the abundance and 
average size of the stones, in the relative abundance of the differ- 
ent kinds, and in the composition of the matrix, the general facies 
remains very constant. All the material so far as discovered is 
of local origin. Owing to a variety of circumstances it is diffi- 
cult to give the thickness with anything like accuracy. 
Details of structure will be best shown in the course of a 
description of the various exposures. The beds are for the most 
part entirely concealed from observation by the overlying depos- 
its. It is only in the vicinity of the river where the latter have 
been wholly or partly removed, or where a deep ravine has pene- 
trated to them that they can be studied. 
Descriptive details —The most extensive exposures occur about 
a mile and a half west of Trempealeau village. A sketch map 
of the locality is given in Fig. 1. At this point'two old valleys 
converge so that they partly unite along the river front. The 
lower parts of these valleys (shown in outline on the map) have 
been filled up so that the drainage has been deflected, resulting in 
the formation of new gorges through the rock. Wherever these 
fillings are open to observation they are seen to consist of unstrat- 
ified beds having the general characteristics above described. 
In the east valley loess occurs down to the bottom of the ravine 
above the filling, many feet below its crest. 
The west valley offers rather the most favorable conditions 
for observation and section 2, Fig. 2, is taken along its axis. The 
filling takes the form of a well marked ridge extending across 
