1890.] | Geology and Paleontology. 1185 
repeated washing processes, until it finally reached its present remarka- 
ble extent and purity. 
The numerous bowlders observed in the region under consideration 
are thought to belong the Drift, and also to represent in part the 
coarser blocks held within the glacial ice.—CLEMENT L. WEBSTER, 
Charles City, Lowa. 
Synopsis of American Carbonic Calyptreidae. By Charles 
R. Keys (Proc. Acad. Nat. Sci. Phila., 1890, pp. 150-181).— This 
paper is a complete résumé of all that is at present known concerning 
the American Carbonic shells, hitherto commonly referred to Conrad's 
genus Platyceras. There are also incorporated many new observations 
derived from an exhaustive study of a large amount of excellent ma- 
terial collected during the past few years, besides an examination of 
nearly all the types of the different forms. Of a single specimen more 
than three hundred specimens were obtained from a single locality, for 
the puposes of determining the limits of variation. While it may be 
regretted that the familiar name established by Conrad nearly half a 
century ago is given up, it is thought the change will be a great'advan- 
tage in the consideration of this group, since it has long been regarded 
by paleontologists who are familiar with the recent shells that Conrad's 
group actually formed a part of Capulus of Montfort. The habits of 
the group are discussed, and the attachment of the shells to Crinoids, 
by which their change of form is attained, is illustrated with many 
examples. It must be borne in mind that the relation of the two 
forms does not imply that the Gastropod was parasitic in its habits, as 
has been generally regarded, but that the mollusc, though for the 
greater part of its life stationary, probably fed on the excrement ot ~ 
the Crinoid. The remarks upon geographic and geologic distribution 
have a wide application. The relations of the forms from the Bur- 
lington and Keokuk rocks are very significant in its bearing upon the 
true connection of the two formations. All known forms and new 
ones are fully described, and a plate of twenty-three figures will aid 
the student in his study of this interesting family. —H. G. GRIFFITH, 
M.D., Burlington, Iowa. 
An Extensive Deposit of Phosphorite Rock in Florida.— 
Prof. E. T. Cox has recently investigated a deposit of this character 
which extends from Middle to Northern Florida in beds of probably 
upper Eocene or Vicksburg age, as determined by Prof. Eugene Smith 
and others. Professor Cox states that ** while the Florida phosphate, 
like apatite, is almost a pure phosphate of lime, yet it differs so widely 
