123 



EOZOIC FORMATIONS. — Continued. 



MONT ALB AN. 



The rocks in Massachusetts here referred to the Montalban 

 series cover a wide area, forming the greater portion of the 

 State. They extend uninterruptedly from the western boun- 

 dary of the Huronian formation to the Triassic sandstones of 

 the Connecticut valley, and spread over most of the area be- 

 tween these Mesozoic rocks and the Hoosac Mountains. They 

 are also wide-spread in the southern portions of Bristol and 

 Plymouth Counties, about the shores of Buzzard's Bay. The 

 Montalban areas on the accompanying map comprise, with 

 slight exceptions, the areas marked as " granite," " gneiss," 

 * ' mica slate," ' ' argillite," ' ' metamorphic slate," and i i quartzite," 

 on the geological maps of Prof. Edward Hitchcock. This series 

 is also, in this State, nearly equivalent to the " White Moun- 

 tain group," " granite," "Merrimac schists," i i calciferous mica 

 schist," and " St. John's group" on the map of Prof. C. H. 

 Hitchcock, in Walking's ''Atlas of Massachusetts," 1871. 



To Dr. T. Sterry Hunt, as is well known, belongs the credit 

 of first correlating the various members of this formation in Mas- 

 sachusetts and announcing their equivalence, collectively, with 

 the similar rocks of Newfoundland, the White Mountain region, 

 and, generally, with a considerable, yet even in the present 

 imperfect state of our knowledge, tolerably definite portion of 

 the belt of crystalline rocks skirting the eastern base of the 

 Appalachians from the Gulf of St. Lawrence to Alabama. 

 This new system, first outlined in a published letter to Prof. 

 Dana, in 1870, was formally announced under the name 

 White Mountain series, in 1871, in an address to the Amer- 

 ican Association for the Advancement of Science, where it is 

 described l as " characterized by the predominance of well-de- 

 fined mica-schists interstratified with micaceous gneisses. 



1 Chemical and Geological Essays, p. 244. 



