8 10 The American Naturalist. [August, 
Section of Makoqueta Shales in Iowa. By Joseph F. James. — 
In this paper mention was made of the locality where the typical 
exposure is to be found. It is near Lattner's Post-Office, reached from 
Graf, a station on the Chicago, St. Paul and Kansas Cit^' railroad, 
sixteen miles west of Dubuque. Details of the section were given, and 
mention made of the fossils found in the shales. A species of Ortho- 
ceras is especially abundant, and remarkable for its wonderful state of 
preservation, many specimens retaining their original pearly nacre. 
Groptobites were also finely preserved, and very abundant in certain 
layers. The junction of the shales with the Galena below was men- 
tioned as having been observed. 
Geology of Borneo Dr. T. Posewitz has published the results 
of three years' personal explorations in Borneo, and in the second part 
of his work deals with the geological and physical structure of that 
large island. There is no uninterrupted central mountain chain, but 
isolated mountains surmount table-lands which extend northeast to 
southwest. As far as is known, the Kina Balu mountains, which have 
a maximum height of 13,698 feet, are the highest. The geological 
structure is simple. The isolated mountains are slate or schist, pene- 
trated by granite and diorite. Succeeding these are Devonian strata 
with auriferous veins. Within the last few years Carboniferous strata 
(mountain limestone) have been found, and are believed to occupy a 
wide area in north Borneo ; and Cretaceous rocks have been found m 
a single locality in west Borneo. The Tertiary is spread over wide 
areas, and forms the plateaus through and over which the mountains 
rise. The older Tertiary includes sandstone, marl and limestone, and 
the greater part of the coral deposits occur in the sandstone. The 
older Tertiary strata are often much disturbed and broken by intrusive 
masses of andesite. Oligocene strata are only known in East Borneo, 
and include extensive deposits of coal. 
Diluvium spreads over wide undulating tracts around the Tertiary 
hills, and contains the principal sources of the gold and diamonds of 
the island. There are no evidences of any post-Tertiary volcanic 
energy. 
Geology of Tasmania.— R. M. Johnson, F.L.S., has published 
a systematic account of the geology of Tasmania, with a sketch map 
on a scale of fifteen miles to the inch. The eldest formations are in 
the west and northeast, and consist of crystalline schists, apparently 
Archaean, with clay slates, quarzites, sand stones and limestones of Cam- 
brian, Ordovician or Silurian age, with small and doubtful evidences • 
