180 The American Geologist. March, 1902 
erties of light are applied to the investigation of thin sections. Crystal- 
lography and the symbols denoting the sides and angles of crystals age 
equally assumed as known by the operator. Naumann’s system is 
used, but with alternative expressions of Miller’s symbols—thus follow- 
ing the practice of the French. This continental condescension to 
the English system perhaps presages the’ ultimate entire adoption and 
use of the simple and meaningful symbols of Miller. 
For American use this little work will serve as a handy compend of 
the essential petrographic characters of the rock-forming minerals. It 
will be useful for reference after the difficulties of mineralogy and 
microscopical manipulation shall have been mastered, and when as a 
teacher or as an investigator the need arises to refer to some authori- 
ty for the established differences existing between minerals. But at 
present there is no need for any English-speaking student to resort to 
works in foreign languages in order to have a guide in petrographic in- 
vestigation, N. H. W. 
Additional notes on the Cambrian of Cape Breton, with descriptions 
of New Species. By G. F. Mattrnew. (Bulletin of Natural His- 
tory Society of New Brunswick, Canada. No, XX, vol. IV, pt. V.) 
The above article is given to a description of the Neotremata of 
the Etcheminian or Basal Cambrian and to the fauna of the Truncado 
beds of the island of Cape Breton in Nova Scotia. The Neotremata 
are represented in the collections from the Etcheminian beds made 
in Cape Breton by three genera, Acropthyra, Acrotreta and Acrothele. 
The first genus is established for a number of forms prevalent in 
the Etcheminian rocks, which there largely replace Acrotreta, tho it 
is to be noted that the latter so far as is known, is of equal antiquity. 
Both are found in the effusive rocks which lie at the foundation of 
the Cambrian sediment, both in New Brunswick and Cape Breton. 
Acrothele, on the contrary, has not been found in the lower Etch- 
eminian fauna, but appears plentifully in the upper. 
In a table bound in with the article, Dr. Matthew shows in synop- 
tical form the parallelism of the several parts of the Cambrian sys- 
tem in the eastern provinces of Canada to the succession which is 
found to exist in Europe, and especially in Wales. Almost all the 
important faunas of the European Cambrian rocks have now been 
found in Canada, as this table shows; and the parallelism is remark- 
ably close, esnecially in the Middle and Upper Cambrian. This fa- 
vors the view that a continuous ocean existed in Cambrian time, be- 
tween the two continents of Europe and America. 
The variations which a number of neotrematous brachiopods un- 
derwent in early Cambrian time is of interest; Dr. Matthew records 
several new species and mutations, which are represented in five 
plates of figures. 
The Tremadoc fauna of the Upper Cambrian is represented by 
several characteristic genera, Asaphellus 2 sp.; Triarthrus, 1 sp.; 
Parabolinella, 1 sp.; Angelina, 1 sp.; Bellerophon, 3 sp.; also Lin- 
