SayLtes.— The Squantum Tillite. 
PLATE 10. 
PEBBLES FROM THE TILLITE. 
Beginning at the upper left hand corner the pebbles from left to right are:— 
quartzite pebble from Roslindale showing subangular shape and fracturing; 
granite pebble from Roslindale showing subangular shape and concave frac- 
tures; melaphyre pebble from Squantum Head showing bevelling and striae; 
quartzite pebble from Franklin Field shown to better advantage in Plate 11; 
quartzite pebble from Roslindale showing bevelling, faint striae, and concave 
fractures; here an attempt was made to show ice bevelling on both sides of a 
central ridge, the ridge is indistinct in this picture. The last specimen was 
found by Dr. Arthur Keith of the United States Geological Survey and con- 
sidered by him at the time as of glacial origin. 
