GEOLOGICAL AND MINERALOGICAL NOTES. 195 



Often found in good rhombic crystals in the amphibolite- 

 gneiss at Putnamville. 

 No. 132. Calcite : Dogtooth Spar. 



Near the Tri-Mountain house, Bass Point, Nahant. 

 No. 133. Calcite: Massive Granulär Limestone. 



Found in large masses at the Devil's Den and Devil's 

 ßasin, Newbury, and at the old lime pits in Boxford. 

 No. 134. Calcite : Massive Blue Limestone. 



Interstratified with quartzite-sandstone and slate in the 

 carboniferous rocks at Topsfield. 

 No. 135. Calcite: Statuary Marble. 



Specimens, pure white and fine grained, occur at the 

 Devil's Den, Newbury. 

 No. 136. Calcite; Silicious Limestone. 



This belongs to the Olenellus, Lower Cambrian period 

 and occurs at Archelaus hill, West Newbury, and at Row- 

 ley and Nahant. 

 No. 137. Dolomite : Magnesian Limestone. 



Found in veins in the Serpentine at the Devil's Den, 

 Newbury. 

 No. 138. Ankerite. 



Good rhombohedral crystals are found in the granitite 

 in the Pomeroy quarry, Gloucester. 

 No. 139. Magnesite: Brown Spar. 



Found in the old Serpentine ledge, Lynnfield Centre, 

 and at Boxford and Newbury. 

 No. 140. Siderite : Spathic Iron. 



Massive crystalline forms are found associated with the 

 iron pyrites and galena at the Chipman mine, Newbury, 

 and (rare) in small Compound scalenohedrons and rhom- 

 bic crystals incrusting the albite feldspars at the Pomeroy 

 quarry, Gloucester. 

 No. 141. Siderite, bronze var. 



In the Newbury mining region. The usual form is 

 granulär in structure. 



