50 BIBLIOGKAPHY OF NOETH AMERICAN GEOLOGY, [bull. 203. 
402 Jaggar (Thomas Augustus). The laccoliths of the Black Hills 
[South Dakota]. 
U. S. Geol. Surv., 21st Ann. Kept., Pt. Ill, pp. 163-290, pis. xviii-xli, 
figs. 60-99, 1901. 
Describes the occurrence of the sedimentary and igneous rocks, and 
the character, occurrence and distribution of the laccolithic intrusives, 
and discusses the physiographic form of eroded domes. 
403 Johnson (D. W.). Notes on the geology of the saline basins of 
central New Mexico. 
Abstract: N. Y. Acad. Sci., Annals, vol. 14, pp. 161-162, 1901. 
404 Johnson (Willard D.). The high plains and their utilization. 
U. S. Geol. Surv., 21st Ann. Kept., Pt. IV, pp. 601-741, pis. cxiii-clvi, 
figs. 300-329, 1901. 
Abstract: Jour. Geol., vol. 9, pp. 734-737, 1901. 
Discusses the origin and structure of the region. 
405 Joly (J.). An estimate of the geological age of the earth. 
Smith. Inst, Ann. Rept. 1899, pp. 247-288, 1901. 
406 Jones (S. P.). The geology of the Tallulah Gorge [Georgia]. 
Am. Geol., vol. 27, pp.*67-75, pis. 9-11, figs. 1-3, 1901. 
Describes the physiographic features of the region and the origin oi 
the gorge. 
407 Julien (Alexis A.). A study of the structure of fulgurites 
Jour. Geol., vol. 9, pp. 673-693, figs. 1-3, 1901. 
Gives the results of the study of four fulgurites. 
408 Erosion by flying sand of the beaches of Cape Cod. 
Abstract: N. Y. Acad. Sci., Annals, vol. 14, p. 152, 1901. 
409 The geology of central Cape Cod [Massachusetts]. 
Abstract: Am. Geol., vol. 27, p. 44 (J p.), 1901. 
Contains notes on the glacial phenomena of the region. 
410 [Discussion of paper b}^ J. F. Kemp on "The Cambro- 
Ordovician outlier at Wellstown, Hamilton County, New 
York."] 
Science, new ser., vol. 13, p. 710, 1901. 
Discusses the origin of the sand in the limestones. 
411 Keith (Arthur). Maynardville folio — Tennessee. 
U. S. Geol. Surv., Geol. Atlas of U. S., Folio No. 75, 1901. 
Describes the geographic features, the stratigraphy, the character and 
occurrence of the Cambrian, Silurian, Devonian, and Carboniferous 
rocks, the geologic structure, and the mineral resources of the region. 
