Review of Recent Geological Literature. 123 
aporhyolite, apoperlite, apobsidian, etc., as to whose exact meaning 
there can be no doubt. In accordance with this usage it is proposed to 
call all the acid volcanic rocks, whose structures prove them once to 
have been glassy, aporhyolites" G. 
Ueber ein neues Vorkonimnis von Kugelgranit unfern Wirvik bei 
Borga in Finland, nebst Bemerkungen ilber dhnliche Bildungen. By 
Benj. Frostekus. (Dissertation, Royal Alexandrian University of Fin- 
land ; 34 pages, 2 plates ; Helsingfors, 1893). 
About twenty miles west of the well known Rapakivi granite is an- 
other granite area, in certain parts of which a beautiful spheroidal 
granite occurs. This forms a basic f acies of the main granite mass, and 
the spheroids (Kugeln) are more basic still. They are of two kinds, 
large and small, and do not occur together. The smaller are from two 
to three centimeters in diameter and are composed of an outer rim of 
biotite, concentrically arranged, and a core of oligoclase, microcline and 
biotite with a more or less pronounced radial arrangement. The larger 
spheroids are twenty to thirty centimeters in diameter and are com- 
posed largely of biotite scales concentrically arranged. A discussion of 
the spheroidal structure is presented and many references are given to 
places where this peculiar structure has been described. The author 
concludes that the true spheroidal structure (Kugelstructur) is a pri- 
mary structure form, that it corresponds to a concretionary development 
during the crystallization of a rock, and that it has a certain connection 
with the older, basic secretions. 
Geological map and table of economic resources of Illinois. By 
Daniel W. Mead. This map, which is in black characters, is based on 
Worthen's map of 1875. The table shows the formations and the local- 
ities where the various economic products are found, also short state- 
ments of the statistics and value of each. This very unique table con- 
tains much useful information, and cost a large amount of study and 
examination, but is injured seriously by its bad arrangement and very 
bad printing. 
Notes on the hydro-geology of Illinois. By Daniel, W. Mead. Read 
before the Illinois Society of Engineers and Surveyors, Jan., 1893. A 
very lucid and also comprehensive exhibit of the sources of artesian 
waters in the state, and a discussion of the chemical impurities of sur- 
face waters. Contains many tables of analyses. 
La Tcrreavant /'apparition <lc Vhomme; pe~riodes ge~ologiqu.es, faunes 
et flores fossiles : giologie rigionqle de la France, par Fernand Priem. 
Numerous cuts. Paris. J. B. Bailliere et Fils. The object of the 
author in this work is to pass in review in a pleasing and simple style 
the changes which the planet has undergone in the different geological 
periods, particularly the faunas and the floras, pointing out the lines in 
which they show some connection with existing faunas or Moras. He 
presents a lively view of the general geology of all countries. He dwells 
more fully on that of France. The treatise evinces a familiarity with 
