THE WESTFIELD PLAIN. 653 



upon sands. These sheets of g-ravel stretclied, L have no (loul)t, rig-ht across 

 the area now occupied by the basin of the Westfield River, and were con- 

 tinuous with the tine gravels just northwest of and al)ove the raih'oad station. 

 Here there is a tlioroughly classified l)ed of 4 to 6 inch pebbles, all well 

 rounded and made up very largxdy of the peculiar hard Tjaurentian gneiss 

 of Washington and Hinsdale and of the Berkshii-e quartzites, both brought 

 down from the headwaters of the Westfield River. 



Mr. Diller calls attention to the depression of the east end of this Ave- 

 nue plain 17 feet below the adjacent ])lains. I believe this i)lain to liave been 

 formed as it now is during the flood time of the main river, and to owe its 

 slope to the heavy flood of the Westfield River, which kept this ])assage 

 between Pochassic Mountain and the West Parish Hills scoured out, ami 

 earned out over its bottom the broad sheets of coarse gravel Avhich reach 

 east to the village of Westfield. The position of these gravels over the 

 underlying sands is the normal one all up and down the valley wherever 

 a delta is advanced into deeper water, and the two beds are parts of the 

 result of a single operation. The flood of the Westfield then, as now, })re- 

 ceded that of the main stream, and thus annually swept its channel clear 

 and gradually built up its hea^'y g•ra^•el beds. 



Poverty plain is continuous across Westfield and into Southwick. 

 It begins to contract in width on the town line, and from Southwick Hill 

 southwai'd has a width of little more than a mile and a half The con- 

 finement of the waters in these naiTOW limits, by increasing their eroding 

 power, seems responsible for the long, shallow depi'ession of the Congamuck 

 or Southwick Pond, and for the curious course of Great Brook, which, 

 starting from the middle of the pond on its west side, runs north among the 

 drift hills, and, leaving them, takes a diagonal course across Poverty plain, 

 passing within 100 rods of the head of the pond, and finding what I imagine 

 was the thread of the current of the main stream and following it Ijack 

 until it joined the Westfield near the divide gorge. 



The tlii-ead of the current passed out of the deep water over South- 

 ampton village and by the west pass down to and across the place where 

 Westfield village now stands, and then, on receiving the watei's of the 

 Westfield rivers, bent east to near the gorge, whence it followed the present 

 course of Great Brook to and across the whole length of Southwick Pond, 

 and so southward across the Farmington basin and by the course of Mill 

 River into the sound at New Haven. 



