90 BULLETIN OF THE ESSEX INSTITUTE. 



Plate I. 

 Fig. 1. Pipe, peridotite ; very probably made of the 

 rock, commonly called soapstone, from the 

 Andover outcrop. 

 Knife blade of Marblehead felsite. 

 Spear-head of Marblehead felsite. 

 Celt or skin dresser of diorite. 



Plate II. 



Slate stone marked as shown. 



Slate tablet, very probably made of the Brad- 

 ford rock. 



Slate tablet, as last. 



Tablet of porphyritic dyke rock. It shows 

 indication of the beginninsr of a hole at the 

 smaller end as in figure 2. 



All of the objects are drawn actual size. In addition 

 to the objects figured, there are in this collection from the 

 Beverly graves, another tablet, similar to fig. 2, Plate If, 

 but of a lighter colored slate ; a porphyritic d>ke rock 

 pebble, with indentations on the edge ; two flat pieces of 

 sandstone, evidently used for rubbing or sharpening imple- 

 ments ; a flat slate stone and two pebbles showing traces 

 of ochre upon them ; and several thin pieces of nmscovite 

 mica of the Andover form of this mineral. The identi- 

 fication of the rock materials has been made by Mr. Sears. 

 There is no reason to suppose that these implements 

 originated outside of Essex County ; for, in each case, a 

 rock of precisely the same character as the object is found 

 within the limits of the county. 



There are, in the county collections of the Peabody 

 Academy, a large number of interesting objects obtained 

 from pre-historic graves, or graves of the people of the 



