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brought to light by another well-boring or the discovery of some 
outcrop. 
It may be briefly stated, according to Mr. Woolman’s conclu- 
sions, that the diatomaceous clay bed immediately overlies an 
Eocene deposit and is beneath a Pleistocene. As will be noticed, 
the diatoms correspond, to a great extent, to those of the great 
Miocene beds of the Atlantic coast, such as the Richmond, Not- 
tingham and Atlantic City deposits; the presence of one form, at 
least, if not two, appears to indicate a correspondence with the 
Barbadoes deposit, which is now claimed to be Pliocene, while 
other forms are still extant. It is, therefore, difficult to determine 
to what period the Florida deposit belongs. 
The following are the forms :— 
Actinocyclus Ehrenbergtt Ralfs, several varities. 
A, ellipticus Grun., rare. 
A. interpunctatus Ralfs. 
A. Ralfsu (Wm. 5m.) Ralfs. 
A, subtilis (Greg.) Ralfs, var. 
Actinoptychus Grundleri A. S. 
A, undulatus Ralfs, several vars. 
_ A. vulgaris Schum., several vars. 
Aulacodiscus Crux Ehr., rare. : 
A. mammosus (var. extans?) Grev., very rare. Diam. 0. 152 mm. 
Surface, central portion, flat to about one-half of the radius, outer 
edge distinct but somwhat turned inward at the inflations, giving 
a slightly quadrangular outline. Central space in one specimen 
round, in the other irregular. Width of bullae adout one-fourth the 
radius. In Greville’s figure the width appears to be about one- 
half. The processes are also smaller in the Florida form. Not 
being able to secure a specimen of Greville’s species for compari- 
son, I am unable to determine the differences further. Mr. Adre. 
Le Tourneur, of Paris, from an examination of a photopraph sent 
him, thinks it may be the variety extans (Grev.) Rattr. This 
beautiful form is quite rare, only two nearly perfect valves and 
three fragments having been noticed. It has not been found, here- 
tofore, we believe, in any other of the continental deposits, and its 
presence appears to link the Florida diatoms with those of Barba- 
does. 
