weeks] PALEONTOLOGY, PETROLOGY, AND MINERALOGY, 1901. 91 
829 Williams (Henry Shaler). [Reviews of "Geological Surveyor 
Canada, new series, vol. 11;" "Geological and Natural 
History Survey of Minnesota, Final Report, vol. 6;" "Iowa 
Geological Survey, vol. 11;" and " Dragons of the air, an 
account of extinct flying reptiles' 1 by H. G. Seeley.] 
Am. Jour. Sci., 4th ser., vol. 12, pp. 394-398, 1901. 
830 Willmott (A. B.). The Michipicoten Huronian area. 
Am. Geol., vol. 28, pp. 14-19, pi. 8, 1901. 
Describes the occurrence of the igneous and sedimentary rocks of the 
region and discusses the stratigraphic succession and age of the sedi- 
ments. 
831 Willis (Bailey). Paleozoic Appalachia or the history of Mary- 
land during Paleozoic time. 
Md. Geol. Surv., Special Publication, vol. 4, pt. 1, pp. 1-93, pis. i-xii, 
fig. 1, 1900. 
Describes the processes of erosion, sedimentation and deformation, and 
discusses the Paleozoic history of Maryland and adjacent States. 
832 Individuals of stratigraphic classification. 
Jour. Geol., vol. 9, pp. 557-569, 1901. 
Discusses the discrimination of formations by lithologic criteria and 
the determination of faunal and time divisions. 
833 Thomas Benton Brooks. 
Science, new ser., vol. 13, pp. 460-462, 1901. 
Gives an account of his life and geologic researches. 
834 Oil of the northern Rocky Mountains. 
Eng. and Mg. Jour., vol. 72, pp. 782-784, 3 figs., 1901. 
Describes the stratigraphy and structure of the region and the prob- 
able occurrence of oil. 
835 Smith (George Otis) and. The Clealum iron-ores, Wash- 
ington. 
See Smith (G. O.) and Willis (B.), 709. 
836 Williston (S. W.). The dinosaur ian genus Creosaurus, Marsh. 
Am. Jour. Sci., 4th ser., vol. 11, pp. 111-114, fig. 1, 1901. 
Reviews previous descriptions and describes new material. 
837 A new turtle from the Kansas Cretaceous. 
Kans. Acad. Sci., Trans., vol. 17, pp. 195-199, pis. 18-22, 1901. 
Describes Porthochelys laticeps, n. gen. et sp. 
838 Wilson (Alfred W. G.). The Medford dike area [Massachusetts]. 
Boston Soc. Nat. Hist., Proc, vol. 30, pp. 353-374, pis. 1-4, 1901. 
Describes the petrographic characters of the crystalline rocks and the 
glacial phenomena of the region. Includes a bibliography and geologic 
map. 
839 Physical geology of central Ontario. 
Can. Inst., Trans., vol. 7, pp. 139-186, 8 pis., 10 figs., 4 maps, 1901. 
Describes the character of the pre-sedimentary floor of the region, 
the characters of the Paleozoic series, its post-Paleozoic history, and the 
glacial phenomena. 
