586 GEOLOGY OF OLD HAMPSHIEB COUNTY, MASS. 



gives e^^dence of the volume of the sands which were carried through this 

 narrow gorge to form the massive delta thrust into the main valley which 

 now remains as a most important portion of the shore bench of the Con- 

 necticut Lake (see p. G39). 



THE LOCKS rOND LAKE. 



Following up Locks Brook into the mountains, we find high sands 

 bordering it with every widening of the narrow valley at all levels until 

 we reach the top of the hills and come upon the broad basin of finely sorted 

 sands surrounding Locks Pond. These I have already connected with the 

 line of sands which can be traced southward through Pelham to Palmer. 

 It is clear, thus, that the ice retreated down this valley, but that its shape 

 did not favor the formation of extended deposits, and its position as a deep 

 transverse gorge extending quite across the block of hills between the Con- 

 necticut and Swift River valleys was such that it intercepted all southward 

 currents so soon as it was free from ice, and it is curious to see how by 

 de^^ous wavs it deposited its burden, now in the Leverett Lake, now in the 

 broad delta at the south end of the Mount Toby Valley, now clogging up 

 the northern end of the latter, while at the last it has contributed very little 

 to the filling up of the Montague basin, into which it now enters from the 

 mountains. 



Locks Pond now lies in the midst of a broad accumulation of fine 

 sands (1 p") which, followed eastward by the road to the Mineral Springs 

 House, ends abruptly on the verge of the steep descent to the Swift River 

 Valley, and this seems to have been at one time an outlet for the lake and 

 to have controlled the height of its waters. 



NOTCHES THROUGH THE HOLYOKE RANGE AND THE LAKE NORTH OF 

 MOODY CORNERS. 



The manner in which the Belchertown notch was occupied by the 

 Pelham River, and in which, by the expansion of this river into the 

 Dwight's station lake, its waters came to occupy also the next pass west — 

 the Bay Road Pass — is detailed in the section on p. 577. These events 

 were the prelude to the complete occupancy of the valley by the lake 

 waters, but at earlier times, immediately following the emergence of the 

 range from the ice, the passes were used as transient watercourses, though 

 no line of esker ridges extends north or south from any one of them. 



