118 [JuLy, 
Dr. Genth read a paper describing a new mineral, Rhodophyllite, which 
was referred to Mr. Vaux, Dr. Wetherill, and Dr. Bridges. 
Dr. Owen, in presenting to the Society a specimen of Fusulina Lime- 
stone, and Tutenmergel, made the following remarks :-— 
The specimen of Fusulina cylindrica is from the carboniferous limestone on the 
west side of the Missouri river, below Fort Kearney. One bed ,of limestone 
there isa complete agglutinated mass of this interesting little foraminiferous 
shell, which is almost the form and size of a grain of wheat, so that those unac- 
quainted with the fossil take it to be “ petrified wheat.?? 
Previous to its discovery on the Missouri river, during the geological survey 
made by me in 1849, it had been found, I believe, only in isolated specimens in 
a siliceous stratum towards the base of the coal measures of Ohio. In Europe it 
has only been found in Russia. Both in this country and Europe it appears to be 
confined to the carboniferous rocks. 
The specimen of Tutenmergel is from Keeth’s Rapid, on the Des Moines river, 
Iowa, where it occurs in great perfection in very perfect cones witha fine 
crimped surface, and possessing internally the structure of Arragonite. The Tu- 
tenmergel of this locality proves to my mind that its form cannot be due to 
simple shrinkage of the strata, as believed by most persons, but is a crystalliza- 
tion, with simultaneous infiltration of calcareous waters—a stalactitic formation, 
not in the atmosphere, but within the substance of its argillaceous matrix. 
The bed at Keeth’s Rapid is only four or five inches thick; but it occurs in 
much thicker beds—nine inches or more—lower down near Amsterdam and else- 
where on the Des Moines, but not inas pure a form, and almost of a black 
color, while the Keeth bed is almost as colorless as calc spar. 
July 20th. 
Vice President BripGss in the Chair. 
Letters were read 
From Professor Lepsius, dated Berlin, June 20th, 1852, accompany- 
ing his donation to the Library announced this evening. 
From Dr. Samuel Webber, of Charlestown, New Hampshire, accom- 
panying specimens of the fins and tail of a Fish, in the substance of 
which were numerous hard granules. The letter also enclosed the fol- 
lowing communication on the subject :— 
<¢In the town of Unity, about twelve miles from the place of my residence, is 
a small body of water known by the name of Cold Pond. It abounds with fish 
of the kind usually found in such waters, viz., roach, bream, perch and pickerel. 
They are plump, firm, and well flavored, but almost uneatable in consequence of 
a peculiarity which I have never observed nor heard of in these kinds of fish in 
other localities. This peculiarity is that through the bodies of these fish are scat- 
tered numerous small blackish grains of a globular form, and of about the size of 
mustard seed, quite hard, and which annoy the teeth so much in theact of masti- 
cation, as to take away all comfort of eating. Sometimes these little bodies are 
single, sometimes clustered together more or less. They pervade even the fins 
and tail, as may be seen by some specimens that I forward in company with this 
brief sketch. Of the nature and cause of this unusual condition of the fish, or of 
the substance of these little pellets, nothing is known. It has been conjectured 
that the water of the pond is more or less impregnated, in parts at least consider- 
‘ably, by some mineral spring, and that the particles of some mineral held in 
solution by it, are taken into the circulation of the fish, and by some process of 
decomposition are deposited in small tubercular aggregations in the various parts 
of the body.”’ 
