\1 
No. 34. — Contour map, in relief, of Washoe mining region, 
50 foot contours. Scale, 1.20000. 
No. 35. — Geological relief map of Blair, Bedford and Hunt- 
ingdon counties, Pennsylvania. A portion dissected to show geo- 
logical structure. 
No. 36. — Profile relief map of the Sentis Mountains, N. W. 
Switzerland, showing mountain contour and geological structure. 
No. 37. — Relief map of the high plateaus of Utah, colored to 
show geological structure. Scale, 1. 1680000. 
No. 38. — Relief map of the Drainage basin of the Arkansas 
river in Colorado, showing the relations of the catchment basins to 
the reservoir sites and irrigable lands. 
No. 39. — Model showing irrigation by ditches and furrows 
on steeply sloping fields. 
Nos. 40 and 41. — Relief maps of Mount Shasta showing 
topographical and geological features. 
Nos. 42 and 43. — Relief maps of the Chattanooga District 
showing topographical and geological features. Note how, by 
folding and erosion, the formations originally overlying one another 
have been exposed so as to succeed one another laterally. 
No. 44.— Relief map of New Jersey showing topographical 
and geological features. 
No. 45.— Relief map of Kentucky showing topographical 
and geological features and location of principal coal fields. 
No. 46.— Relief map of Missouri showing topographical 
and geological features and principal mining districts. 
No. 47.— Relief map of the United States showing limits and 
theoretical curvature of the ancient ice sheet at the stage of the 
Glacial Period following the main silt epoch. Modelled on a sec- 
tion of a globe i6>£ feet in diameter. Scale, 1 inch equals 40 miles. 
Relief Maps of Volcanoes and Volcanic Regions. 
No. 51 .— Relief map of the region of extinct volcanoes in 
Auvergne, Central France; geological and topographical. Henri 
Le Coq and G. P. Scrope. 
No. 52 .— Relief map of the Ice Spring craters, a group of 
extinct volcanoes near Fillmore, Utah, illustrating the successive 
