PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 31 
It also means that listed fossils from the lower formation are either long ranged 
or misidentified. The Isle la Motte formation is overlain by the Larrabee forma- 
tion which is correlated with the Hull formation of Ontario and western New 
York because of abundance of Parastrophina. 
PHILLIPSBURG THRUST SLICE 
In southern Quebec, just north of the Vermont border and on the east side 
of Lake Champlain, a long sequence of Ordovician rocks is revealed in the 
Phillipsburg slice which is thrust over the Iberville shale. Most of this slice 
is composed of Lower Ordovician formations but these are overlain by the 
Mystic conglomerate or breccia (Clark, 1934, pp. 6, 7). This formation is com- 
posed of limestone boulders of varying size, often quite large. These boulders 
are of several ages but the ones of immediate interest here are the youngest ones. 
These are of gray, granular limestone abounding in fossils related to those of 
the Table Head series of Newfoundland. This assemblage is of considerable 
interest because the fauna is known nowhere in the vicinity in an undisturbed 
sequence. Affinities with the highest Pogonip of Nevada are also apparent. 
Brachiopods from the youngest boulders are: 
Acrotreta magna Cooper Palaeoglossa mysticensis Cooper 
Bimuria ? matutina Cooper Paucicostella canadensis Cooper 
Camerella breviplicata Billings Pleurorthis convexa Cooper 
C. polita Billings P. corinna (Billings) 
Hesperonomiella quebecensis Cooper P. costellata Cooper 
Idiostrophia costata Ulrich and Cooper P. fascicostellata Cooper 
I. perfecta Ulrich and Cooper Ptychoglyptus sp. 1 
Idiostrophia sp. 1 Rhysostrophia elliptica Ulrich and Cooper 
Neostrophia subcostata Ulrich and Cooper R. transversa Ulrich and Cooper 
CHAMPLAIN VALLEY (EAST SIDE) 
In west-central Vermont Cady (1945, pp. 548-554) described a series of Chazy 
rocks which are mostly poorly fossiliferous and of uncertain classification. The 
sequence from the top down is Middlebury limestone, Beldens formation, and 
Crown Point limestone. The last limestone is about 60 feet thick at Orwell, Vt., 
but thickens to 150 feet to the north. It is mostly gray, compact, massive lime- 
stone containing Maclurites “magnus” (LeSueur). The Beldens formation is 
buff-weathering dolomite interbedded with white marble. The formation con- 
tains the Weybridge member consisting of limestone with thin sandy streaks. 
The formation ranges up to 700 feet in thickness. Fossils are very rare. The 
Middlebury limestone, which attains a thickness of about 600 feet, is dark, blue- 
gray, partially dolomitic limestone with buff streaks. 
In northwestern Vermont Kay (1945, p. 1171; 1947, p. 601) described a 
sequence consisting of the Beldens white, dense limestone 500 feet thick, fol- 
lowed by the Carman quartzite 60 to 125 feet thick. The latter is succeeded by 
the Youngman formation composed of argillaceous limestone grading upward 
into dark slate with interbedded limestone. The Youngman formation contains 
the brachiopod Christiania and the trilobite Lonchodomas halli (Billings). 
