DEPARTMENT OF THE INTERIOR,
UNITED STATES GEOLOGICAL SURVEY,

Washington D. C., July 1, 1884.

SIR: Herewith I have the honor to transmit the first of my prelimi

ry studies on the Cambrian Faunas of North America.

The faunas studied are under discussion at the present time, and an rly publication is desirable.

Very respectfully,

Hon. J. W. POWELL,

Director U. 8. Geological Survey.

(285)

CHARLES D. WALCOTT.

CONTENTS.

I.-Letter of transmittal....

II.-Review of the fauna of the Saint John formation, contained in the Hartt

collection.....

III.-Fauna of the Braintree argillites.....

IV. On a new genus and species of Phyllopoda from the Middle Cambrian....