36 ~ Observations by T. A. Conrad 
This mineral is interesting as differing very much from every 
titaniferous mineral hitherto analyzed, in containing water. This 
fact connected with the presence of a silicate of magnesia, sug- 
gests the idea that it is an altered mineral, which finds addi- 
tional support from its locality and associated minerals. The 
magnesian limestone in which it occurs, often contains crystals 
having the forms of spinelle and pyroxene, but converted into a 
soft hydrous mineral resembling steatite,a change which has evi- 
dently resulted from the introduction of a silicate of magnesia 
with water. If the mineral under consideration was originally 
a compound of oxides of titanium and iron with perhaps alu- 
mina, we should expect the form of the crystal to be a rhomboid 
like that of specular iron or ilmenite. Our present knowledge 
of the laws of ll Bian appears inadequate to the decis- 
ion of this question. - 
Yale College Laboratory Febennies 1846, - 
Prats 
Arr. V. — Observations on 1 the Soaaey of a part of Hat Florida, 
with a Catalogue tf Recent Shells of the Coast ; bigs T. A. 
3 _ Conran. 
~Havine ere some rile to the Tertiary Vetoes ‘of 
the Atlantic coast, I have endeavored to ascertain their relation to 
European formations. With regard to the Eocene of particular 
localities, no difficulty was experienced, because all the species of 
shells were extinct, and yet no Cretaceous forms or characteristic 
genera, such as Baculites, Hamites, &c., occurred in those places. 
‘This fact alone was sufficient to indicate the Eocene origin of the 
strata in question, but when such shells as Cardita planicosta, 
Corbis lamellosa, Ostrea bellovacina, and others equally character- 
istic of the European Eocene, were found in company with many 
species having a close affinity with shells of the Paris basin, the 
evidence was perfectly conclusive. The upper series of Tertiary 
strata, [have ever regarded as equivalent in stratagraphical pa 
to that portion of the English crag which contains Voluta 
berti and Isocardia rustica, and whilst that formation was steel 
to the Older Pliocene, the term was used to distinguish the Amer- 
ican equivalent. The error was one of terms-alone, and has long 
nich args 
ce 5 aaa ee he Lig 
