HISTORICAL SKETCH. xlv 
In this paper Dr. Whiteaves describes the following: 
Maclurea manitobensis. Widely distributed. 
Poterioceras nobile, East Selkirk and Lower Fort Garry. 
Poterioceras apertum, Dog’s Head, Winnipeg lake. 
Oncoceras magnum. Fast Selkirk. 
Oncoceras gibbosum, Swampy island, and Jack-Fish bay, etc. 
Cyrtoceras manitobensis, Deer island, Big island, etc. 
Trochoceras me’charlesi, East Selkirk. 
Aspidoceras insigne. Stony mountain. 
“On purely paleontological evidence the highly fossiliferous deposits of Stony mountain were referred 
to the Hudson River formation by the present writer, in 1880,* and the fossils of the pale buff-colored 
limestones or dolomites of East Selkirk and Lower Fort Garry have long been supposed to show that these 
rocks are the equivalents of the Galena limestone or upper portion of the Trenton formation of Wisconsin 
and Iowa. On the same evidence the somewhat similarly colored and fossiliferous limestones of the 
islands and shores of lake Winnipeg appear to be of the same age as the Trenton limestone proper, or at 
any rate not older than the Birdseye and Black River group of eastern Canada and the state of New York. 
It is possible that the fossiliferous rocks on the shores and islands of lake Winnipeg may be a little lower 
down in the series than those at East Selkirk and Lower Fort Garry, but the whole of these deposits, 
apart from those at Stony mountain and elsewhere in Manitoba which can be someWhat confidently re- 
ferred to the Hudson River group, probably represent only one well-defined horizon in the Cambro-Silurian 
system. However this may be, in the writer’s judgment there is at present no satisfactory paleontologi- 
cal evidence for the existence of the Chazy formation or its equivalent in Manitoba,” p. 838. 
C. H. Gordon. 
1889. Notes on the Geology of Southeastern Iowa. By C. H. GorpoN, American 
Geologist, vol. Iv, p. 237, Oct., 1889. The records of some deep wells are given, viz: At 
Keokuk the Maquoketa shale, struck at 800 feet, developed a thickness of 63 feet, and the 
Galena and Trenton combined a thickness of 140 feet. At Ottumwa the Maquoketa shales 
appeared at 955 feet and they apparently continued to the depth of 1045 feet, with the des- 
ignations ‘‘lime and sandrock,” given by the drillers, a thickness of 99 feet. The Galena 
and the Trenton can scarcely be recognized under the designations given. At Sigour- 
ney the Maquoketa has a thickness of 165 feet, and was struck at the depth of 10380 feet. 
The Galena and Trenton have a thickness, apparently, of 113 feet. 
C. W. Hall. 
1889. The lithological characters of the Trenton limestone of Minneapolis and St. Paul, 
with a note on the borings of the West hotel artesian well. By C. W. Hau. Bulletin of the 
Minnesota Academy of Natural Sciences, vol. 10, p. 111, 1889. 
The author gives the stratigraphic order in detail, and the chemical and petro- 
graphic characters. 
Frank Leverett. 
1889. Studies in the Indiana Natural Gas Field. By FRANK LEVERETT. American 
Geologist, vol. Iv, pp. 6-21, July, 1889. This paper contains a valuable tabulation of the 
data of gas wells, both in Indiana and in Ohio, by which it is shown that the ‘‘lower 
shales,” 7. e., the Cincinnati shales and limestones, extend unbroken, though with some 
variations of dip, and with diminishing thickness, toward the west from the Cincinnati 
anticlinal. From 1100 feet in Union and Madison counties, Ohio, their thickness is 
reduced to less than 400 feet in Cass and Carroll counties, Indiana. Mr. Leverett shows 
*Geol. Sur. Can, Rep. Progr. 1878-79, p. 50C, 
