Reviczv of Recent Geological Literature. .49- 
New Species of Cambrian Fossils from Cape Breton. By G. F. Mat- 
thew. (Bulletin, Nat. Hist. Society of New Brunswick, vol. iv, 
p. 219.) 
Under this head Dr. Matthew has described a number of Upper 
Cambrian species of trilobites and brachiopods that are of consider- 
able interest. 
A good deal is made of the internal character of the shells of the 
brachiopods, which are carefully described. The species belong to the 
genera Lingulella, Lingula ? Acrotreta and Schizambon. The example 
of the last genus is a small species more orbicular than the type, and of 
interest as carrying the genus back to Cambrian time. (The typical 
form described by Walcott is of Ordovician age.) The Acrotreta is 
remarkable for the heavily truncated mould of the ventral valve, and 
for the unusually strong medium septum of the dorsal valves. 
Among the trilobites the largest species is a Parabolina distinct 
from others in the strongly arched front margin of the head shield. 
A very remarkable form is a species of Sphaerophthalmus, carrying a 
very large flat genal spine, differing from S. alatus in this and other 
respects. An Agnostus of generous size is a Canadian mutation of A 
trisectus Salter ; it is peculiar in having a tubercle at the end of the 
rachis of the pygidium, and in other respects. These trilobites are of 
the Peltura fauna ; the brachiopods chiefly of this fauna and that of 
Dictyonema (D Habelliformis). 
.\ plate with figures of the species and mutations described accom- 
panies the article. N. H. w. 
The Action of Ammonium Chloride upon Natroh'te, Scokcite, Prehnite 
and Pectolite; by F. W. Cl.\rk and George Steiger. {Am. J. 
Sci., I6<9 345-351.) 
The present paper is one of a series having for an object the study 
of the chemical constitution of certain silicates. The minerals were sub- 
jected to the action of ammonium chloride in sealed tubes at a tempera- 
ture of 350°, and the resulting products analyzed. The action of a 
boiling, 25% solution of sodium carbonate was also tried on them. 
Both natrolite and scolecite are unattacked by the sodium carbonate 
solution and yield with the ammonium chloride the same compound 
(NH4)2 AI2 Sis Oio, which is a simple replacement of the bases and 
acid hydrogen of the minerals by the (NH4) radical. From these facts 
and an entirel)' new and complete analysis it is concluded that the two 
minerals are salts of the same silicic acid Hg 813 Oio, and that their 
formulas should be written Na2 AI2 Sis Oio -2 H2O for natrolite, Ca W^ 
Sis Oio • 3 H2O for scolecite instead of the previously accepted orthosil- 
icate formula} AI2 (Si 04)s Na2 H4. and AI2 (Si O4) Ca H4 . H2O respect- 
ively. Prehnite suffers no change when treated as above and is there- 
fore of different structure. Pectolite, a meta-silicate Na H Ca2 Sis O9, 
although attacked strongly by the chloride, did not yield results leading 
to any new or more definite conclusions as regards its structure. 
c. H. w. 
