358 Progress of North American [April, 
howelli is very interesting. The discovery in the Devonian of 
the interior of a dorsal valve of Lingula whitei proves the great 
similarity of structure between the Lingule of the Silurian, 
Devonian and recent time. A commingling of Upper Devonian 
and Lower Carboniferous fossils occurs; there occurs also a 
gradual transition from the beds containing Olenellus howell 
through beds containing a fauna similar to the Potsdam of New 
York, to beds containing a fauna comparable to that of the chazy 
and calciferous groups. The transition is very gradual, and such 
as would occur where there had been no marked physical dis- 
turbance. In the Bull. U. S. Geological Survey the same author 
has “ Preliminary studies on the Cambrian faunas of N. America.” 
These are in three parts, the first is “ A review of the fauna of 
the St. John formation, contained in the Hartt collection.” This 
work is not meant to encroach on that of Mr. Matthew. Mr. 
Walcott does not accept the genus Conocephalites, and refers its 
different species to Ptychoparia and one of Conocoryphe. The 
second part is on the “ Fauna of the Braintree Argillites.” The 
third part contains the description of a new genus and species 
of Phyllopoda from the Middle Cambrian slates of Parker’s farm, 
Georgia, Vermont. In Science, Vol. m1, the same author has an 
article on the “ Appendages of the Trilobite;” he notes the veri- 
fication of the hypothesis that the legs were jointed beneath the 
pygidium as the only addition to our knowledge furnished by 
Mr. Mickleborough’s specimen, 
Lester F. Ward, in the Amer. Your. of Sci. and Arts, has an 
article “ On Mesozoic Dicotyledons.” 
C. A. White, in the Rep. of the Secretary of the Interior for 
1883, Vol. 11, gives “A review of the fossil Ostreidæ, North 
America, and a comparison of the fossil with the living forms. 
With appendices by Professor Angelo Heilprin and Mr. John A. 
Ryder.” This work is on the same plan as that followed in the 
review of the non-marine fossil Mollusca published the year pre- 
vious. In the Bull. of the U. S. Geological Survey, No. 4, the 
author has three articles, the first, “ On a small collection of Me- 
sozoic fossils collected in Alaska, by Mr. W. H. Dall, of the U. 
S. Coast Survey.” The author considers these forms to belong 
to beds occupying a transitional position between Cretaceous and 
Jurassic, as previously suggested by Professor J. Marcou. The 
_ second is a “ Description of certain aberrant forms of the Chami- 
