4 ’ 
cies on the coast, or under circumstances which prove them to have been alive 
at no very remote period. It is not unusual to meet with some of these in 
the Delaware tidal mud, and a still larger number are to be found in the blue 
clay (old estuary) deposit immediately underlying it. Among these a few of the 
most common are, Eupodiscus Ralfsii, E. argus, Coscinodiscus gigas, 
C.ocul-iridis, C. centralis, Triceratium striolatum, T. puncta- 
tum, Actiniscus siriu s, &e., Sceptroneis caduceus, occurs living on 
alge ‘at Riviere du Loup, St. Lawrence river, Goniothecium obtusum at 
Black Rock Harbor, L. I. 
The important question, too, of the influence of locality on the growth and 
development of species no where presents itself in so interesting a point of 
view as in this country. The large extent of its sea board, embracing every 
variety of climate, the continuous chains of estuaries and sounds along the 
entire line of coast, and the many rivers, large and small, traversing every kind 
of soil from the southern alluvial to the granite ranges of the north east, offer 
an unsurpassed field for the study of this influence. 
Although not able to pursue the subject at this time, I cannot refrain from 
alluding to a fact which forces itself on the mind at an early stage of these in- 
vestigations, viz.: the great distance from the sea at which marine influences 
continue to make themselves felt. Philadelphia is situated nearly a hundred 
miles from the ocean, and even at the period of spring tides at least fifteen 
miles above the faintest suspicion of brackish water, and yet quite a number 
of the diatoms in the Delaware at this point are purely marine, and a still 
larger number brackish. The agency of migratory fish, as the shad and low 
swimming sturgeon, in bringing about this result, is no doubt important, but 
will not serve to explain the presence of brackish and marine species in the 
ditches adjoining Cooper’s Creek, a tributary of the Delaware, and in Fox Chase 
Run, some ten miles above this city, at points not within tidal range. The 
old estuary bed of the Delaware (blue clay) before alluded to, was very rich. 
in these forms, and by digging down a short distance at any part of the meadow 
land bordering the river, the blue clay which contains them may be exposed. 
An idea which naturally suggests itself under these circumstances as a solu- 
tion of this paradoxical difficulty is, that possibly the telluric impression of 
the subjacent soil may continue to make itself felt in the development of spe-. 
cies for a long period after the other surroundings have ceased to be favorable. 
At all events it needs some other explanation than that ordinarily had re- 
course to, viz., the hardihood ofthese low forms of organic life, and the agency 
of birds and fish, to account for the permanent localization of marine species at 
points apparently so unsuited to their existence. 
I. New species and Sporangial forms. 
1. Triceratium alternans, Bailey. Sporangial 2—This somewhat doubtful 
form has so few of the characters of T. alternans, that but for the occur- 
rence of intermediate varieties the propriety of its reference to that species 
might seem questionable. The structure of the valve is distinctly cellular, in 
the smaller varieties indistinctly so, and that of the obtuse processes faintly 
punctate. The largest frustules attain the size of T. favus. 
Hab.—St. Mary’s river, Ga., inscum of a salt marsh.’ 
2. Surirella pulchra, nsp. F.V. Linear narrow, often somewhat twisted. 
V. Ovate or elliptical, ale distinct, canaliculi numervus, marginal inflated as 
in S. fastuosa, 6in ‘001, extending for about two-fifths of the distance to 
centre of valve, central portion smooth circumscribed on either side by a 
coarsely striated arcuate band with harshly defined edges, and connected with 
its fellow at a short distance from the end of the valve. Immediately exterior 
to these bands, and separating them from the inner termination of the canali- 
culi throughout the entire length of the valve, is a corresponding only some- 
what narrower arcuate smooth space. Length of valve -005 to ‘009. Pl, I. f. 1. 
This very beautiful form, evidently allied to 8. fastuosa and 8, eximia, 
Mic. Journ., differs from poth in the greater number of its canaliculi and the 
eh 
