460 Scientific Intelligence. 



ume of the series dealing with individual counties has been pre- 

 pared in accordance with the plan announced some years ago of 

 furnishing reports dealing with various parts of the state, the 

 plan being to include in one volume all the important geological 

 matter pertaining to a given section. 



From an economic standpoint, little criticism can be made of 

 these reports since they discuss not only coal, gas, oil, building 

 stone and clay, but also soils ; but as general reading books deal- 

 ing with the geology of the section, they are not so satisfactory. 

 It is a legitimate part of the work of a State Survey to publish 

 the results of geologic research in a form which may be of use to 

 schools and to the average intelligent man. The publications of 

 the Wisconsin, the Illinois and the Connecticut Surveys indicate 

 how this may be done. 



The maps published with this volume are especially good, and 

 the idea of combining the county maps into one map for the 

 whole district is to be commended. h. e. g. 



3. New Zealand Geological Survey ; J. M. Bell, Director. 

 Bulletin No. 8 (New Series). The Geology of the Whangaroa 

 Subdivision, Hokianga Division, by J. M. Bell and E. DeC. 

 Clarke. Pp. v and 107, illustrations xvii, maps 8, geological 

 sections 4. — Little geological work has previously been done in 

 the area covered by this report, the northern edge of Auckland 

 Island, although this part of New Zealand contained one of the 

 earliest settlements and is widely known as a producer of kauri 

 gum, which next to gold has contributed most to New Zealand 

 revenues. 



The rocks of this area include pre-Cretaceous, argiliites, quartz- 

 ites, and igneous rock ; late Mesozoic and early Tertiary, the 

 Kaeo series of sedimentaries ; Miocene, the Wairakau breccias, 

 dikes and flows ; Miocene or post-Miocene, Kerikeri flows and 

 underlying sediments ; post-Miocene lake beds, acid and basic 

 volcanics. Since the deposition of the Wairakau series tectonic 

 movements include little folding but extensive faulting. The 

 surface as a whole is a faulted tableland deeply dissected and 

 with volcanic cones rising above the level. The shore line is that 

 of a typical depressed land surface. There are evidences of base- 

 leveling on the surface of the Kaeo rock and renewed peneplana- 

 tion occurred between Wairakau times and the extrusion of the 

 Kerikeri volcanics. Rock benches are developed along the shore 

 line, but they are believed not to represent planes of marine ero- 

 sion, but rather to be due to the cooperation of subaerial weathering 

 and marine transport. The freshwater lakes occupy basins due 

 to damming by lava flows or explosion craters. 



Chapters 4 and 5 of this report (pp. 41-79) are devoted to 

 detailed descriptions of the stratified rocks with their fossils and 

 the igneous rocks, including a number of analyses. In the chap- 

 ter on economic geology (pp. 80-98), an interesting account is 

 given of the occurrence of mercury, which seems to be directly 

 associated with hot springs, as in the case of certain Nevada and 

 California deposits, discussed by G. F. Becker. h. e. g. 



