THE CHICOPEE ItlVEH DRAIXAdE. 575 



upper waters of Mountain Brook, tlo\vin<>- nortli. Following- this brook for 

 a long distance with the sands, the latter end abruptly and overhang Sunny 

 Valley, which was plainly filled with ice when these sands were laid down 

 The bottom of Sunny A^alley, far below, is also covered with the tine- 

 grained. Hat sands of a still later lake. 



On Tully River, the last of the series, the sands Itegin where, in the 

 east of Warwick, the Royalston road crosses the river (b", PI. XXX\', C). 

 Aljove, the deep, open valley is continuous a long way north in two 

 branches, favorably shaped and situated to receive and retain sands, l)ut 

 now covered with coarse bowlders. Drawing a line through the jjoints 

 thus fixed in the preceding paragraphs from Tannery Bi-ook in Montague 

 (p. 573) to Tully River (see PI. XXXV, C), and assuming— which admits 

 of little doubt — that they represent points along a continuous ice front, we 

 see that wliile the ice still projected in a lobe down the Connecticut \'allev 

 the ice front extended toward the northeast from Montague and pi-essed 

 foi-ward in a blunt lobe between Mount Grace in Warwick and Bear Hill 

 in Wendell. See also page 604 for the continuation of this barrier on the 

 west of the Connecticut Vallev. 



THE CHICOPEE RIVER DRAINAGE. 

 THE BELCHERTOWN LAKE. 



With the breaking down of the barriers (1/, PI. XXXY, D) described 

 above, the Quaboag, Ware, and Swift rivers were admitted to the Belcher- 

 town plateau and became tributaries of the Belchertown Lake. Standing in 

 the middle of the broad, square plain of fine sands which stretches east from 

 Three Rivers, we are shut in on the east and south by high, rocky hills 

 notched for the passage of the three streams mentioned above, and on the 

 west by a Inroad, low ridge which on its west side slopes down to the vallev 

 of the Connecticut. At the southwest corner tlie western ridge sinks 

 down, and the lake was ultimately drained at this point, the Chicopee River 

 cutting a deep canyon in till and rock to join the Connecticut, and its 

 three branches dissecting tlie old lake bottom and showing how gi-eat 

 was the volume of sand gathered there. It was so great, indeed, that they 

 nowhere cut through it. The lake extended up the valleys of each of these 

 three rivers in the form of broad erosion plains on each side of the streams, 

 commencing at the same level with the lake sands and rising slowlv with 

 the streams. 



