Review of Recent Geological Literature. 329 
cal map of Nova Scotia on the scale of a mile to an inch. The general 
popular interest in the work of the survey is well indicated by the 26,- 
785 visitors of its museum. Field work has been prosecuted by fourteen 
parties, of which two were in British Columbia, one in the Northwest 
Territory (boring 1,731 feet without yet reaching the petroleum-bearing 
strata at Athabasca Landing), one in Manitoba and Keevvatin (explor- 
ing the country east of lake Winnipeg), four in Ontario, four also in 
Quebec, and two in Nova Scotia. Brief reports of the observations of 
these parties are presented, in which attention is especially directed to 
the economic resources of the several regions examined. w. u. 
Studies of Pal&echinoidea. By Robert Tracy Jackson. (Bull. 
Geol. Soc. America, vol. vn, pp. 171-254. 7 plates; Rochester, 1896.) Of 
late years unusual activity has been shown in America in the detailed 
examination of the fossil echinoderms according to modern morpholog- 
ical methods. Instead of efforts being directed to the endless multipli- 
cation of species, as in most other groups, all energies have been bent 
towards inquiries leading to a better understanding of the structure 
and of the genetic relationships of the forms. Clark has already issued 
his first installment on the Mesozoic echinoderms, Wachsmuth and 
Springer have just completed the first part of their monumental work 
, on the fossil crinoids, and now Jackson has appeared with a most wel- 
come presentation of his studies on the Paleozoic echinoids, which have 
led to the proposition of an entirely new classification of the group. 
The studies originated in a detailed examination of the structure of 
Melonites, the notes of which appear in another place. A few new spe- 
cies have been described, but the diagnoses are so complete and full of 
detail, and the comparisons with related forms so elaborate that one 
cannot but.regret that the author's work does not include in its scope a 
similar treatment, in the same happy manner, of all of the known spe- 
cies, since so many of them are so poorly defined or almost unknown. 
The facts and theoretical considerations are carefully separated, the 
latter being brought out in the concluding paragraphs. 
In regard to the taxonomic arrangement the author finds that a "nat- 
ural systematic classification of Paleozoic Echini can be based on the 
features of the anatomy and development of the ambulacrum and in- 
terambulucrum and the relations of the peristome to the ventral border 
of the corona. While these features are the main ones, others are con- 
sidered in the minor divisions of the group, such as imbrication of 
plates, the form of plates and the position of ambulacral pores. This 
classification, which is presented in tabular form, is distinctly intended 
as a systematic arrangement, in which the species, genera, families and 
orders are arranged so as to express their structural relations in a nat- 
ural order. It is not intended as a phylogenetic table. While the phy 
logeny would probably follow somewhat similar lines, there are so rnanj 
great gaps that it could not be stated that this is the true genealogical 
history of the group. In the table details of structure are given for 
each division from class to species, so that in this consideration of the 
table only additional and general features are discussed." 
