Geology and Mineralogy. 473 



present in America at a horizon corresponding to that at which 

 it occurs in Europe it should show itself in band b of Division I, 

 but so far it has not been recovered from this horizon ; on the 

 contrary the species found to be associated with it in the Kenne- 

 becasis Basin are mostly those that belong to band d or higher 

 measures. 



In Newfoundland 0. (?) Kjerulfi occurs in association with 

 Agraulos strenuus, Hyolithes Micmae, etc. The two species 

 named occur in Division I, band c in the St. John Basin, and 

 the second occurs also in d. 



Olenelhis (?) Kjeridfi, was originally described as a Paradoxides 

 by Linnarsson, but Prof. W. C. Brdgger referred it subsequently 

 to Olenellus. It is perhaps doubtful it' the species belongs there : 

 the peculiar pygidiurn of Olenellus has not been recorded in con- 

 nection with it, and the eyelobe is that of Paradoxides. But on 

 the other hand the glabella is not enlarged in front as in the true 

 Paradoxides, and all the furrows turn backward as in Olenus and 

 other genera of the Middle Cambrian. Among true Paradoxides, 

 P. Acadicus in its straight-sided glabella, its moderately arched 

 and uniformly narrow eyelobes, and its granulated test, appears 

 to be more closely allied to this species than any other. 



St. John, N". B., Aprii, 1886. 



2. Geological formations underlying Washington and vi- 

 cinity. Report of the Health Officer of the District of Columbia, 

 for the year ending June 30, 1885. [By Smith Townsend, 

 M.D., Health Officer.] Washington, 1886. (8vo, pp. 1-160, fold- 

 ing plates 1-16 + 3.) — In addition to the customary sanitary, 

 hygienic, statistical and administrative matter, this l'eport con- 

 tains the substance of a communication from the office of the 

 IT. S. Geological Survey, embodying some preliminary results of 

 -an elaborate survey of the District of Columbia, in which the for- 

 mations underlying Washington and its environs are for the first 

 time clearly discriminated and named. 



It appears that Washington is located in a triangular depres- 

 sion or amphitheatre, rising 20 to 80 feet above tide, bounded 

 on the east, north, and southwest by bluffs rapidly ascending by 

 successive terraces to altitudes of 150 to 300 feet, and traversed 

 by the Potomac river, the Eastern Branch, and some minor 

 streams. Within this amphitheatre and rising about its periphery 

 (except on the east) to an altitude of about one hundred feet is 

 a well defined Quaternary deposit to which the name Columbia 

 formation is applied. Its upper portion consists of loam or brick- 

 clay, and its lower of sand, gravel, bowlders (up to four or five 

 feet in diameter), or all combined. Its thickness is variable, the 

 upper member ranging from almost nothing to perhaps 20 or 30 

 feet, and the lower from perhaps 1 to 20 feet. The deposit is 

 more or less distinctly stratified throughout, particularly in its 

 lower division; and at the base it frequently becomes a simple 

 bed of bowlders and gravel, without considerable admixture of 

 finely comminuted materials. The entire formation appeal's to 



Am. Jour. Sci. — Third Series, Vol. XXXI, No. 186. — June, 1886. 

 30 



