34 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
Austin Glen member.—This member is composed of thick and thin beds of 
grit and shale, but the former predominates. The member is chiefly confined to 
the west side of the river. Fossils are rare in the Austin Glen member, but a 
few graptolites, eurypterids, and other fossils have been taken. Brachiopods are 
not reported. Corynoides and Diplograptus are two important graptolites of 
this member. 
Overlying the Normanskill formation is an interesting conglomerate contain- 
ing pebbles of several formations, and known as the Rysedorf conglomerate. 
Rysedorf conglomerate.—This conglomerate is of varying thickness, from 
a few feet to 50 feet. Ruedemann (1930, p. 104) states “The Rysedorf con- 
glomerate has a wide distribution within the Normanskill shale belt in the capi- 
tal district; but it also extends into the Schuylerville quadrangle, where the 
writer has described it from the base of Bald Mountain (’14, p. 80) ; and it is 
found at Schodack Landing and may be identical with the Burden conglomerate 
described by Grabau from Becraft mountain near Hudson.” 
The pebbles of the Rysedorf conglomerate are of several kinds: gray lime- 
stone of early Cambrian age, black crystalline limestone with Bolboporites, said 
to be Chazy limestone (not necessarily so because Bolboporites is common in 
the lower part of the Edinburg formation in Virginia), Lowville limestone with 
Tetradium cellulosum, and black compact limestone with a prolific fauna related 
to the Chambersburg of Pennsylvania and the Edinburg formation of Virginia. 
This fauna is of considerable interest because it is impossible to derive it from 
any known source near Albany. The brachiopods of this suite of black limestone 
pebbles are: 
Christiania trentonensis Ruedemann 
Crama trentonensis Hall = Petrocrania trentonensis (Hall) 
*Dalmanella testudinaria (Dalman) = Paucicrura ? 
Leptaena rhomboidalis Wilckens = L. ordovicica Cooper 
Orthis tricenaria Hall (sic) = Hesperorthis sp. 
*Platystrophia biforata (Schlotheim) 
*Plectambonites sericeus (Sowerby) 
P. pisum Ruedemann = Bilobia pisum (Ruedemann) 
Rafinesquina alternata (Emmons) = Macrocoelia ruedemanni (Salmon) 
Siphonotreta minnesotensis Hall and Clarke 
Ruedemann correlates this fauna with that of the Chambersburg limestone, 
but the part of that formation is not stated. Christiania occurs throughout the 
Edinburg formation which is a southwestward extension of part of the Cham- 
bersburg formation, but some of the other fossils occur more commonly in the 
Oranda formation just above the Edinburg such as Leptaena, Rafinesquina, and 
Hesperorthis. The possibility of these pebbles having been derived from the 
Youngman formation of Vermont should not be overlooked. This formation also 
contains Christiania, but the rest of the fauna is not known. 
The presence of Platystrophia in these pebbles of the Rysedorf conglomerate 
is probably an error of identification. This genus has not yet been seen in the 
Chambersburg or Edinburg formations. It is suggested that Oxoplecia has been 
mistaken for Platystrophia. The Rysedorf conglomerate also reminds one 
