250 The American Geologist. April, 1896 
There are given under each: (1) a summary of the observations of those 
authors who have contributed to a knowledge of the particular species; 
(2) references, which, though inaccessible, are an aid in the determina- 
tion of the geological range and geographical distribution; (3) a com- 
parison of the invalid forms; (5) a discussion of the forms related to the 
types: and lastly (6) the author's own observations. Five large triple 
plates accompany the memoir. c. k. k. 
The Physical Features and Geology of the Route of the proposed Ot 
tawa Canal between the St. Lawrence River and Lake Huron. By R. 
W. Ells and A. E. Barlow. (Trans. Royal Society of Canada, second 
series, vol. i, section iv, pp. 163-190, with map; 1895.) This paper pre- 
sents a hydrographic and geologic description of the route surveyed, 
with a series of carefully determined altitudes of the rivers and lakes, 
in their stages of low and high water. The route follows the Ottawa 
and Mattawa rivers to the source of the latter in Trout lake, 667 feet 
above the sea. A watershed which is reported to be less than three feet 
higher divides this from lake Nipissing, only about three miles distant, 
lying 25 feet below Trout lake: and its outlet, French river, has a de- 
scent of 61 feet to lake Huron. The question whether an outflow from 
the lake Huron basin, since the retreat of the ice-sheet, passed eastward 
across this watershed, as supposed by Gilbert, Wright, and Spencer, is 
not here taken up: but elsewhere Mr. Barlow and Dr. Robert Bell have 
expressed their opinions against that hypothesis. The character and 
origin of the Archaean formations, which occupy nearly all the country 
from Allumette island of the Ottawa river to Georgian bay, and'the his- 
tory of their investigation by Canadian geologists, are quite fully con- 
sidered. Within the last ten years it has been shown "that many of 
these rocks, formerly supposed to be sedimentary, are, in fact, truly 
igneous masses." w. u. 
The Physical Geography of Southern X<>tc England. By W. M. 
Davis. (National Geographic Monographs ; American Book Co., New 
York, 1895.) This article traces the origin of the upland of New Eng- 
land as a very ancient peneplain of erosion on which rise a few old 
relics of yet higher land in the shape of " monadnocks " or isolated 
points that have survived the base-level erosion. The dissection of this 
peneplain is next explained, the date of the uplift being uncertain. The 
action of the rivers in this work comes next, that of the Connecticut 
standing foremost, and in this connection the author very justly points 
out that the great size of this valley is not due simply to the size of its 
contained river, and also that the broad Connecticut lowland is the 
first step to a lower plain or base-level which must some day be reached. 
The lava ridges, incipient " monadnocks " of the second peneplain, are 
next discussed and the essay concludes with a notice of the relation of 
population to the physical geography of a region. The paper is illus- 
trated by several excellent photographic reproductions. E. w. c. 
