Review of Recent Geological Literature. 115 
Ohio University, Athens, O., Prof. A. D. Merrill 1 
Proctor, John R., Franklin, Ky., Aug-. 19, '88 1 
Rose Polytechnic School,. Terre Haute, Irid., Aug. 19, '88 1 
Read, Jas. P., Calico, San Bernard Co., Cal., Aug. 31, '88 1 
Oberlin College, Ohio, Aug. 23, '88 1 
Frazer, Dr. Persifor, Philadelphia 1 
Streater Township High School, La Salle Co., 111. R. William 
Price, Sept. 21, '88 1 
State Univ., Athens, Ga., Prof. J. W. Spencer, Nov. 12, 1888. . . 1 
Lowry, Thos., Minneapolis, Minn., Nov. 13, 1888. (N. H. Win- 
chell), Nov. 13 1 100 
REVIEW OF RECENT GEOLOGICAL 
LITERATURE. 
Ueber die Graptoliten; Inaugural-dissertation. By Carl Wiman. 
(Bull. Geol. Inst. Upsala, no. 4, vol. n, pt. 2. pp. 1-74, pis. 9-15, 1895). 
The revival of interest in the study of the graptolites has been largelj 
due to the application of refined preparative methods to the isolation 
of the colonies and the microscopic analysis of their structure. Wiman's 
paper is somewhat general in scope and brings out many important 
points in the morphology and histology of certain genera, e. g., < 'limaco 
graptus, Retiolites and Dictyonema, yet we conceive that irs most 
attractive portion to the paleontologist may prove to be that in which 
the author details the technique of his preparative treatment of these 
delicate fossils. So full of suggestive hints is this part of the paper to 
all who interest themselves in seeking the clew to nature's best work 
among the fossils that we present these experiments without much 
abridgement. 
Gumbel, Holm and Tornquist have isolated the graptolites by var 
ious methods, either dissolving them from a calcareous matrix with 
acid or with the help of Schultze's medium, which is a solution of 
calcium chlorate in nitric acid. The treatment of the specimen varies 
with the nature of the matrix. Sweden has furnished many instances 
of graptolites preserved in limestone, in contradistinction to America 
where such a mode of preservation is not frequent. The handling of 
such material, if the matrix is comparatively pure,. is simple. If the 
solution is to be conducted on a moderately large scale, commercial 
muriatic acid is used, but as even (lie ebullition of the gas, if violent. 
may break the delicate fronds, it is often requisite to use caution either 
by dilution of the acid or by the use of a milder solvent, such as acetic 
acid. Crude muriatic acid contains more or less sulphuric acid which 
in reaction with the limestone produces gypsum and this is likely 
to crystallize about the fronds unless the process be arrested or the 
solution decanted before such crystallization sets in. With the close of 
the process most of the delicate fronds will have dropped into the mini 
dy residuum and their extraction will require careful manipulation. 
