1879.)  “ Turtle-Back” Celts in District of Columbia. 113 
dug, because that lies nearer the slope which rises at an angle of 
about 16°. This fluviatile drift, as it seems to be, formed the bed 
of an ancient body of water; but whether the implements found 
date to that period or a little later, it is impossible to decide. 
Were it possible to continue the search by digging at various 
places and depths to ascertain if the implements occur elsewhere 
than at the bluff, more might be learned, though it is very im- 
probable, as will be shown farther on. 
Dr. F. M. Endlich informs me of the occurrence of ancient 
shore lines on the eastern declivity of the neighboring hills, which 
may mark the surface of the same stratum occurring on the 
western side, as the continuation may be traced interruptedly 
around the hills, following the course of the Schuylkill river. 
The implements found at the last named locality present no 
appreciable difference from those occurring at Uniontown. Their 
conformation, mineralogical composition, typical workmanship 
and even the color of the materials correspond in all respects. 
Forms from Reading are figured in the American Antiquarian‘ 
by Mr. Berlin. Some in my possession are identical in form, but 
several are more typical of that class found in the drift at Trenton 
by Dr. Abbott, and the illustration? given by him represents one 
celt perfectly. This striking similarity is certainly remarkable ; 
and considering the persistence with which the New Jersey celts 
are reproduced at Reading and at Uniontown, there appears to be 
greater relationship between the manufactures of the three varie- 
ties than has been accredited, or that we may be able to account 
for. One, and it may be be considered the strongest objection to 
this suggestion, is, the difference in altitude above the tide water 
between the several localities. Another is in regard to the geo- 
logical positions of the implements. 
In another locality, one mile south-west of Reading, on the 
right bank of the Schuylkill river, numerous specimens of these 
similar rude implements have been obtained. They likewise con- 
sist of the same species of quartzite, and are typical “ turtle- 
backs.” This locality covers about two or three acres in extent, 
sloping very prominently towards the river. The soil is sandy, 
and differs in this respect from that lying immediately around it, 
has been under cultivation for the last sixty or seventy years, and 
1 Vol i, No. I, pl, facing p. 16, figs. 1-3. 
2 Tenth Ann. Rep. Peabody Mus., i, 1877, p. 33, fig. 1, a-b. 
8 
VOL. XIII,--NO, II, 
