556 THE JOURNAL OF GEOLOGY. 
the Madison level. During this stage the lower terraces and 
deltas observed in the intra-moraine basin were formed, and per- 
haps also the gravel beds without the moraine near Madisonville, 
80 feet below the maximum water level. The Upper Preakness 
stage was probably a short one, since the terraces are not of 
great size and deposits of this character were undoubtedly made 
very rapidly. In order to account for the lowering of the lake 
level it is necessary to suppose that the lake had at this time a 
subglacial outlet. This might readily have been brought into 
existence as the ice retreated towards the Little Falls gap. There 
are, however, some difficulties involved in this assumption. These 
will be noticed later. 
The Montville stage —lf the higher terraces are younger than 
the lower, it must be further assumed that the low stage of the lake 
was followed by a rise of the water approximately to the Madison 
level. The name Montville is proposed for this stage of the lake. 
During this stage there were formed the high-level delta plains 
and terraces north of Parsipanny, near Boonton, north of Mont- 
ville, at Jacksonville, north of Upper Preakness, west of Haledon 
and at Caldwell. The ice retreated a little between the Upper 
Preakness stage and the Montville stage, and the deltas of the 
latter were built a little back of and above those of the former. 
In some cases the higher plains reached and partially buried the 
lower ones. The Montville stage seems to have been a little 
longer than the Upper Preakness stage. In a few places possible 
shore-lines have been noted at elevations between those of the 
Montville stage and those of the Upper Preakness stage, but it 
has not been possible to correlate them definitely with each other, 
or to make out their time relationship to other shore-lines. They 
are best shown on the inner face of the moraine, south of Mont- 
ville, near Caldwell, and northeast of New Vernon. 
If the preceding conclusions as to the relative ages of the 
Upper Preakness and of the Montville shore-lines be correct, we 
must conclude that the rise of the water to the Montville level 
was brought about by the closing of the subglacial outlet. It 
must be confessed that it is difficult to understand how such an 
