1S8 W. UPHAM — MODIFIED DRIFT IN SAINT PAUL. 



and the union between the second and third is by a tract of gravel and 

 sand a mile wide, with an undulating and rolling surface; but the fourth, 

 fifth, and sixth, and the three little plateaus continuing eastward from 

 the sixth, are isolated from each other, and in each instance are wholly 

 surrounded by lower land. 



1. SUMMIT A VENUE PL A TEA U. 



Most conspicuous among these plateaus is the most southern one, which 

 is crossed by Summit avenue. It was formerly called Saint Anthony 

 hill, because the road leading from the original village and steamboat 

 landing in Saint Paul to Saint Anthony (now the east part of Minne- 

 apolis) passed over it. More commonly at the present day it is known 

 simply as *' the hill." Its extent as a high plain two miles long from 

 east to west, with an average width of one mile, has become well built 

 up with residences, chiefly during the last ten years. 



From the Trenton limestone terrace on the south the steep ascent of 

 this plateau is 110 to 125 feet, to the broad, nearly level plain, which 

 varies in height from 910 to 920 feet, and in some places 925 to 928 feet, 

 above the sea. The Trenton shales extend, in this southern ascent, 60 

 to 75 feet above the limestone, and are capped by about 50 feet of the 

 modified drift. On the north the descent from the plateau is 75 to 25 

 feet, decreasing westward. On the west its level gravel and sand abut 

 upon a slightly higher tract of moderately rolling and knolly till, which 

 presents in some parts the characteristic topography, of a marginal 

 moraine. 



The southern border of the western part of the plateau, at Ridgewood 

 park, where the Chicago, Milwaukee and Saint Paul railway curves north- 

 westward, has a thickness of about 100 feet of stratified gravel and 

 sand. From this maximum, the thickness of the modified drift dimin- 

 ishes* to its north central portion, where the underlying till in a few 

 places extends up to the surface, while on Dale and Carroll streets, and 

 for an eighth of a mile eastward, the Trenton shales, as before noted, 

 outcrop in a low ridge 25 feet above the gravel plain. 



2. HAM LINE PLATEAU. 



Narrowly connected with the Summit Avenue plain by a tract of sand 

 and gravel an eighth to a quarter of a mile wide, having the same height 

 as the large plains on. the east and north, the Hamline plateau or plain, 

 925 to 940 feet above the sea, thence extends two miles northward, with 

 a width varying from one mile to nearly two miles. Along the east side 

 of the connecting sand tract and of the wide Hamline plain, there is a 

 descent from that plain of 25 to 40 feet, to smooth till areas thinly 



