Dodge.] 
210 
[May 18, 
It is noticeable that in the westerly part of this long narrow 
valley, the ledges do not lie in a direction from each other corre- 
sponding to their strikes, for these are more to the northward 
than is the trend of the belt of territory which contains the out- 
crops. The rocks are too often drift-covered for complete working 
out of the stratigraphy. 
JSTeponset Conglomerate. The outcrops for the half mile 
southward of the Welles Avenue exposure are too few to make 
plain the relations of the rocks here. Puddingstone seems to fol- 
low upon the slate in natural succession, but the region is deeply 
covered with drift and strewn with boulders ; then too, the near 
approach of the area of older rocks which Mr. Crosby has shown 
extends to Washington Street, indicate, if not a break, a shallow- 
ness in the stratified deposit remaining at this place, which 
would show them liable to interruption of their continuity by 
irregularities in shape of the underlying felsite surface. 
Along the south side of the felsite and amygdaloid the dip is 
still to the south. This is shown at Hyde Park, also five-eighths of 
a mile east of the Mattapan station (N. Y. & N. E. R. R.) and on 
the east side of Dorchester Avenue south of Codman Street. 
Work is carried steadily forward at the city quarry south of 
Codman Street, and while excellent opportunities are thus afforded 
of observing facts in regard to the rock, they are as rapidly lost, and 
permanently. The puddingstone has frequently occurring layers of 
sandstone. The dip is about 35° northwestward. The pebbles dif- 
fer somewhat from those at the Roxbury quarries. Felsites like 
those at Mattapan occur among them. Some pebbles resemble 
closely, to the eye, some portions of the rock which is extruded 
through the stratified beds. Pebbles of a stone composed of 
rounded fragments are found. 
Between the quarried puddingstone and Dorchester Avenue 
are several limited exposures of slate. Just east of the Avenue, 
opposite the Cemetery, and about forty feet from where a small 
private way leaves the Avenue, is one ledge in low ground. The 
strike here is 1ST. 53° E. — S. 53° W., the dip S. E. 55°. 
About 140 yards from Codman Street, and 125 yards from Dor- 
chester Avenue, measured perpendicular to each, is slate in a gravel 
pit in a hillside. Here the slate contained small folds, apparently 
