22 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
Sowerbyella punctostriata (Mather) 
*S. sericea (Sowerby). (Identification doubtful.) 
**Strophomena billingsi Winchell and Schuchert 
S. filitexta Hall 
S. f. obesa Wilson 
S. magna Wilson 
S. ? millionensis affinis Wilson 
S. rotunda Wilson 
S. venustula Wilson 
Trematis terminalis (Emmons ) 
Trigrammaria trigonalis prima Wilson 
Triplecia cuspidata (Hall) = Triplesia cuspidata (Hall) 
T. extans (Emmons) = T. extans (Emmons) 
**V ellamo trentonensis (Raymond) 
Zygospira recurvirostris (Hall) 
Correlation of Rockland formation and remarks on the listed brachiopods.— 
The Rockland formation has hitherto been correlated with the upper part of the 
Decorah of the Mississippi Valley, but the above list indicates that the Ottawa 
Valley Rockland formation contains elements of the Prosser formation of the 
Mississippi Valley as well. Prosser elements are: Vellamo, Platystrophia, On- 
niella, and Parastrophina. 
The discrepancies in the above list are interpreted as defects in the listing 
rather than indicating that the Rockland formation correlates with the Decorah 
and Prosser of the Mississippi Valley. If this were the case the Hull and Sher- 
man Fall formations would need to be completely reevaluated. The work of Kay 
has shown these to be consistently identified over wide areas. The writer has 
therefore placed the Rockland in the position and correlation given it by Kay 
(1937). 
HEAD OF THE ST. LAWRENCE VALLEY IN NEW YORK AND ADJACENT CANADA 
This area includes the Black River Valley of New York, the Watertown area 
of New York, and the adjacent part of Ontario along the north side from Kings- 
ton westward. The Ordovician about Coboconk described by Okulitch (1939) 
is on the westward side of the belt. The Black River rocks of this area were 
described by Young (1943) and the Early Trentonian by Kay (1937). The 
area is a well-known one numbering several formations almost as old as the 
science of geology in New York. From the bottom up the section is: Pamelia, 
Lowville, Chaumont (including several members), Rockland (with two mem- 
bers: Selby and Napanee). 
Pamelia formation.—This formation has its greatest thickness in Jefferson 
County, N. Y., where it is 150 feet thick. It consists of a lower division of about 
70 feet composed of basal conglomerate and arkosic sandstones, dark-gray fos- 
siliferous rock, sublithographic limestone interbedded with gray dolomitic lime- 
stone. The upper division is about 80 feet thick, of light-gray or whitish earthy 
limestone interbedded with gray magnesian and sublithographic limestone. In 
both divisions the dolomitic and earthy limestones weather to a buff or yellow- 
ish-brown hue, and are thus readily distinguished from the overlying Lowyville. 
