1895.] MICROSCOPICAL JOURNAL. 331 



much might be seen of the natural outcrops as left ex- 

 posed along the })ublic road. The highest summit or 

 ridge crossed had a probable elevation of some six hun- 

 dred feet above sea level. Examinations made of the 

 strata of various })oints, showed the material to be made 

 up of various degrees of induration of the Radiolarian 

 clays, ranging from complete flinty silicification to clays 

 quickly softening to muds on immersion in water. The 

 latter (readily reduced clays) were remarkable for the 

 richness of the foraminiferal forms and for the simple 

 arcuate sponge s})icules contained therein. The various 

 samples of rocks tested showed a variation in the rich- 

 ness of the contained Radiolarian bodies, some samples 

 approximating a richness of fossil contents equal to the 

 deposits derived from the Barbadoes chalks. They con- 

 tained a relatively limited number of species in associ- 

 ation, probably some twenty or more, but they might be 

 aggregated together, or concentrated to any required ex- 

 tent. All of the Radiolarian clays of these deposits gave 

 a combination of Radiolarians, Diatoms, Foraminifera, 

 and s})onge s})icules. The s})icules, as a rule, were of a 

 rather complex pattern, branched and bifurcated on the 

 order of elks' antlers. Owing to the difficulty of reduc- 

 ing or eliminating the amorphous clay matrix in which 

 the fossils are embedded, the best results that the mate- 

 rial is capable of yielding have not thus far been attained. 

 I speak with reference to the richness of species contained 

 in the material. My usual method for determining the 

 presence and collecting the Radiolarians, is to tritu- 

 rate, or rub the softened clay on a small flat square of 

 india-rubber. During repeated washings there is a final 

 and complete elimination of all clay sediments, leaving 

 the sand grains, mica, and various fossil bodies as a resid- 

 uum. After this the silicious fossils of the several 

 kinds may be secured by tens of thousands, but at the 

 cost of destruction of the more delicate and minuter 



