56 The American Geologist. January, 1892 
of certain western-central counties tributary to Kansas City, G. E, Lapp. 
Mr. Haworth apparently reverses at once the prevalent idea of the origin 
of the crystalline rocks ofMissouri. Formerly Prof. Pumpelly had repre- 
sented them as largely or wholly derived from sediments, and Swallow 
had only admitted the granites and the porphyries to be eruptive. Mr. 
Haworth notes in the field the following evidences of their eruptive 
origin, (1) absence of true bedding, (2) flow and banded structure and 
lithophysve, (8) breccia, (4) scoria and amygdalcids, (5) tuffs, (6) absence 
of gradation of crystalline into non-crystalline rock. The petrographic 
evidence he discusses under the following divisions, (1) texture of the 
ground mass in the porphyries and breccias, (2) flow structure in the 
porphyries and breccias, (3) broken crystals due to flowage of the lava 
after the crystals were formed, (4) Magmatic corrosion of porphyritic 
crystals and of fragments in the breccia, (5) amygdaloids, (6) absence of 
metamorphic minerals. 
The rocks, taken together, he accepts as “Archean,” but he does not 
define Archean. When it be remembered that “Archean” has been made, 
very generally, until quite recently, to embrace all crystalline rocks below 
the Lower Silurian, but that there is a complex of primordial crystallines, 
as lately demonstrated in Minnesota and New Jersey, which has an im- 
portant bearing on the limits of the true Archean, it would have been 
wellif Mr. Haworth had gone a step further, if possible, and indicated 
whether it is not likely that the crystalline rocks about Pilot Knob belong 
to the crystallines of Taconic age. Their lithology seems to exclude 
them from the true Archean, and to point to the Labradorian, or erup- 
tive age of the Taconic. 
Descriptions of Four New Species of Fossils from the Silurian Rocks of 
The Southeastern, Portion of the District af) Baskatchenan, By asain 
Wurrkaves. This small pamphlet of ten pages and one plate is re- 
printed from 7’he Canadian Record of Science. April, 1891. The fossils 
described were discovered by Mr. J. B. Tyrrell while making explora- 
tions for the Geological Survey of Canada. The localities are on Cedar 
lake and on the Saskatchewan river below Cedar lake. The horizon is 
Upper Silurian. The species are Strophomena acanthoptera, Pentamerus 
decussatus, Gomphoceras parvulum, and Acidaspis perarmata. 
Contributions to Canadian Micro-paleontology. Part Ill. By Pror., T. 
RureErt Jonsgs, F. R.S., F. G.S. The sub-title of this paper, Ov some 
Ostracoda from the Cambro-Silurian, Silurian and Devonian Rocks, fully 
expresses its scope and object. There are forty-one pages of text and 
four plates. 
Laboratory Practice, « series of experiments on the fundamental principles 
of chemistry. A companion volume to“The New Chemistry.” By Jostan 
Parsons Cooke, LL.D. 12 mo, 192 pp., 1891, D. Appleton & Co., New York. 
This little book is what it purports to be; the chemical principles are 
demonstrated by simple experiments, and during their performance 
exact observation and careful noting of all phenomena are inculcated. 
There are first several experiments with water, demonstrating its density, 
expansion by heat and by freezing, its distillation, conductivity of heat, 
. 
