68 BIBLIOGRAPHY OF NORTH AMERICAN GEOLOGY, [bull. 271. 
Howe (Ernest). 
1. An occurrence of greenstone schists in the San Juan Mountains, 
Colorado. 
Jour. Geol., vol. 12, pp. 501-509, 1904. 
Describes the occurrence and character of greenstone schists in the San Juan J 
Mountains, discusses their age, and compares them with similar rocks from 
other localities. 
Hubbard (George D.). 
1. An inter-Glacial valley in Illinois. 
Jour. Geol., vol. 12, pp. 152-160, 3 figs., 1904. 
I >r<cribes distribution of Illinoian and Wisconsin drift deposits in southern 
Illinois and various physiographic features of the Embarras Valley, and dis- 
cusses its physiographic history. 
Huntington (Ellsworth) and G-oldthwait (James Walter). 
1. The Hurricane fault in the Toquerville district, Utah. 
Harvard Coll., Mus. Comp. Zool., Bull., vol. 42 (Geol. Ser., vol. 6), pp. 199- 
259, pis. i-vii, figs. 1-13, 1904. 
Describes geographic and physiographic features of the region, the charade: 
and occurrence of the geologic formations, the geologic history, embracing 
deposition, uplift, folding, faulting, erosion, and vulcanism, and the occur 
rence and effects of lava flows. 
Hyde (Jesse E.). 
1. Changes in the drainage near Lancaster [Ohio]. 
Ohio Naturalist, vol. 4, pp. 149-157, 4 tigs., 1904. 
Discusses changes in drainage produced by the ice invasions of the Glacia 
period. 
I. 
Iddings (Joseph P.). 
1. A fracture valley system. 
Jour. Geol., vol. 12, pp. 94-105, 1 pi., 1904. 
Discusses the relations subsisting between systems of drainage and fracture; 
and describes in illustration the drainage system and geologic structure ( 
the Livingston Quadrangle, Folio 1 of the Geologic Atlas of the Unite 
States. 
2. Quartz-feldspar-porphyry (graniphyro liparose-alaskose) froi 
Llano, Texas. 
Jour. Geol., vol. 12, pp. 225-231, 1904. 
Describes petrographic characters and chemical composition, and discusses i 
position in the quantitative system of classification. 
Irving (John Duer). 
1. The ore deposits of the northern Black Hills. 
Mg. Rep., vol. 50, pp. 430-431, 1904. 
Describes the general geology and the occurrence, geologic relations, and eha 
acter of the gold, silver, tin, and wolframite ore deposits. 
2. Ore deposits of the northern Black Hills. 
U. S. Geol. Surv., Bull. no. 225, pp. 123-140, 1904. 
Describes the general geology and the character and occurrence of ore depc 
its, chiefly gold, lead-silver, and wolframite, in Algonkian, Cambrian, Ct I 
boniferous, and eruptive rocks. 
