Quartzose Breccia. 



319 



ular quartz, connected by oxide of iron ; or of fragments of mica slate, 

 surrounded by radiated quartz. The variety found in bowlders in 

 Leverett and Amherst, (I have no doubt that the bed from which they 

 were derived is in Leverett, )contains but very little iron, scarcely more 

 than enough to give a part of the fragments a reddish hue. (Nos. 602, 

 to 608.) Another variety I have found in Amherst, in connection with 

 the gneiss formation, in which the cement is magnetic oxide of iron. 

 But the most interesting variety exists in numerous bowlders along 

 the western slope and base of Hoosac mountain. It consists of angu- 

 lar fragments of white and reddish granular quartz cemented by 

 brown hematite. (Nos. 604 to 606.) In the cavities the hematite is 

 often iridescent and mamillary ; and the coat investing the fragments, 

 fibrous. The largest bowlders of this rock that I have seen, (6 to 8 

 feet in diameter,) occur on the Pontoosic turnpike from Pittsfield to 

 Springfield, in the south part of Dalton, at the foot of the Hoosac range. 

 But I have never found this rock in place. It maybe that the loose 

 fragments have all proceeded from a huge vein of this breccia. But 

 from their size and abundance, I rather presume that this rock will be 

 found as a bed in the common granular quartz of the vicinity. I 

 found one bowlder of this rock ten inches in diameter, in Southamp- 

 ton ; only two or three miles from Connecticut river ; affording an- 

 other proof of a northwesterly diluvial current in former times. 



Professor Dewey remarks, that in Great Barrington and Sheffield 

 the fragments of quartz are united by a cement of quartz. 



The most common gangue of the lead and manganese ores in 

 Hampshire and Franklin counties, is quartz. In a majority of cases 

 it is radiated quartz investing nuclei of micaceous slate. Thus is pro- 

 duced a very curious kind of breccia. (No. 608,) And since these 

 veins are sometimes 6 or 8 feet thick, the quantity is great enough to 

 deserve a notice in this connection. 



9. Quartzose Conglomerate. This consists of a paste of quartz and 

 mica, in which are imbedded numerous distinctly rounded pebbles of 

 granular or hyaline quartz. (Nos. 609, 610.) It possesses as complete- 

 ly the characters of a conglomerate as any of the puddingstones of the 

 secondary formation. I have never found it in place ; but cannot 

 doubt that it is associated with the quartz rock of Berkshire county. 

 For its bowlders are not uncommon on the west slope and the top of 

 Hoosac mountain. In Windsor I found them unusually abundant. 

 I have even found small bowlders in the Connecticut valley, in Deer- 

 field. It appears to be identical with the Conglomerate Quartz Rock 



